<?xml version="1.0" encoding="us-ascii"?><InstanceReport xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"><Version>2.4.0.8</Version><ReportLongName>0006 - Disclosure - ORGANIZATION AND BASIS OF PRESENTATION</ReportLongName><DisplayLabelColumn>true</DisplayLabelColumn><ShowElementNames>false</ShowElementNames><RoundingOption /><HasEmbeddedReports>false</HasEmbeddedReports><Columns><Column FlagID="0"><Id>1</Id><IsAbstractGroupTitle>false</IsAbstractGroupTitle><LabelSeparator>

</LabelSeparator><CurrencyCode /><FootnoteIndexer /><hasSegments>false</hasSegments><hasScenarios>false</hasScenarios><MCU><KeyName /><CurrencySymbol /><contextRef><ContextID>From2013-01-01to2013-06-30</ContextID><EntitySchema>http://www.sec.gov/CIK</EntitySchema><EntityValue>0001031927</EntityValue><PeriodDisplayName /><PeriodType>duration</PeriodType><PeriodStartDate>2013-01-01T00:00:00</PeriodStartDate><PeriodEndDate>2013-06-30T00:00:00</PeriodEndDate><Segments /><Scenarios /></contextRef><UPS /><CurrencyCode /><OriginalCurrencyCode /></MCU><CurrencySymbol /><Labels><Label Key="CalendarSupplement" Id="0" Label="6 Months Ended" /><Label Key="Calendar" Id="1" Label="Jun. 30, 2013" /></Labels></Column></Columns><Rows><Row FlagID="0"><Id>1</Id><IsAbstractGroupTitle>true</IsAbstractGroupTitle><LabelSeparator>

</LabelSeparator><Level>1</Level><ElementName>ecte_NotesToFinancialStatementsAbstract</ElementName><ElementPrefix>ecte_</ElementPrefix><IsBaseElement>false</IsBaseElement><BalanceType>na</BalanceType><PeriodType>duration</PeriodType><IsReportTitle>false</IsReportTitle><IsSegmentTitle>false</IsSegmentTitle><IsCalendarTitle>false</IsCalendarTitle><IsEquityPrevioslyReportedAsRow>false</IsEquityPrevioslyReportedAsRow><IsEquityAdjustmentRow>false</IsEquityAdjustmentRow><IsBeginningBalance>false</IsBeginningBalance><IsEndingBalance>false</IsEndingBalance><IsReverseSign>false</IsReverseSign><FootnoteIndexer /><Cells><Cell FlagID="0" ContextID="" UnitID=""><Id>1</Id><IsNumeric>false</IsNumeric><IsRatio>false</IsRatio><DisplayZeroAsNone>false</DisplayZeroAsNone><NumericAmount>0</NumericAmount><RoundedNumericAmount>0</RoundedNumericAmount><NonNumbericText /><FootnoteIndexer /><CurrencyCode /><CurrencySymbol /><IsIndependantCurrency>false</IsIndependantCurrency><ShowCurrencySymbol>false</ShowCurrencySymbol><DisplayDateInUSFormat>false</DisplayDateInUSFormat></Cell></Cells><ElementDataType>xbrli:stringItemType</ElementDataType><SimpleDataType>string</SimpleDataType><IsTotalLabel>false</IsTotalLabel><UnitID>0</UnitID><Label>Notes to Financial Statements</Label></Row><Row FlagID="0"><Id>2</Id><IsAbstractGroupTitle>false</IsAbstractGroupTitle><LabelSeparator>

</LabelSeparator><Level>2</Level><ElementName>us-gaap_OrganizationConsolidationAndPresentationOfFinancialStatementsDisclosureTextBlock</ElementName><ElementPrefix>us-gaap_</ElementPrefix><IsBaseElement>true</IsBaseElement><BalanceType>na</BalanceType><PeriodType>duration</PeriodType><IsReportTitle>false</IsReportTitle><IsSegmentTitle>false</IsSegmentTitle><IsCalendarTitle>false</IsCalendarTitle><IsEquityPrevioslyReportedAsRow>false</IsEquityPrevioslyReportedAsRow><IsEquityAdjustmentRow>false</IsEquityAdjustmentRow><IsBeginningBalance>false</IsBeginningBalance><IsEndingBalance>false</IsEndingBalance><IsReverseSign>false</IsReverseSign><FootnoteIndexer /><Cells><Cell FlagID="0" ContextID="From2013-01-01to2013-06-30" UnitID=""><Id>1</Id><IsNumeric>false</IsNumeric><IsRatio>false</IsRatio><DisplayZeroAsNone>false</DisplayZeroAsNone><NumericAmount>0</NumericAmount><RoundedNumericAmount>0</RoundedNumericAmount><NonNumbericText>&lt;p style="font: 11pt/normal Times New Roman, Times, Serif; margin: 0; text-align: justify; text-indent: 0.5in"&gt;&lt;font style="font-size: 10pt"&gt;&amp;#160;&amp;#160;&amp;#160;&amp;#160;We
are a medical device company with expertise in advanced skin permeation technology.&amp;#160;&amp;#160;We are developing our Symphony&lt;/font&gt;&lt;font style="font-size: 7pt"&gt;&amp;#174;&lt;/font&gt;&lt;font style="font-size: 10pt"&gt;
CGM System (&amp;#147;Symphony&amp;#148;) as a non-invasive, wireless continuous glucose monitoring (&amp;#147;CGM&amp;#148;) system for use
in hospital critical care units and for people with diabetes.&amp;#160;&amp;#160;The Prelude&lt;/font&gt;&lt;font style="font-size: 7pt"&gt;&amp;#174;&lt;/font&gt;&lt;font style="font-size: 10pt"&gt;&lt;b&gt;&amp;#160;&lt;/b&gt;SkinPrep
System (&amp;#147;Prelude&amp;#148;), a component of our Symphony CGM System, allows for enhanced skin permeation that will enable extraction
of analytes such as glucose.&amp;#160;&amp;#160;Prelude&amp;#146;s platform skin preparation technology also allows for needle-free, transdermal
drug delivery. Additional applications for needle-free analyte extraction and topical and systemic drug delivery are planned.&lt;/font&gt;&lt;/p&gt;

&lt;p style="font: 10pt/normal Times New Roman, Times, Serif; margin: 0; text-indent: 0.5in"&gt;&amp;#160;&lt;/p&gt;

&lt;p style="font: 10pt/normal Times New Roman, Times, Serif; margin: 0; text-align: justify; text-indent: 9pt"&gt;&amp;#160;The accompanying
unaudited consolidated financial statements include the accounts of the Company and its wholly-owned subsidiary, Sontra Medical,
Inc., a Delaware corporation. All significant intercompany balances and transactions have been eliminated in consolidation.&amp;#160;&amp;#160;These
financial statements have been prepared in conformity with generally accepted accounting principles (&amp;#147;GAAP&amp;#148;) in the
United States consistent with those applied in, and should be read in conjunction with, the Company&amp;#146;s audited consolidated
financial statements and related footnotes for the year ended December 31, 2012 included in the Company&amp;#146;s Annual Report on
Form 10-K as filed with the United States Securities and Exchange Commission (&amp;#147;SEC&amp;#148;) on March 18, 2013.&amp;#160;&amp;#160;These
financial statements reflect all adjustments, consisting only of normal recurring adjustments, which are, in the opinion of management,
necessary for a fair presentation of the Company&amp;#146;s financial position as of June 30, 2013 and its results of operations and
cash flows for the interim periods presented and are not necessarily indicative of results for subsequent interim periods or for
the full year.&amp;#160;&amp;#160;These interim financial statements do not include all of the information and footnotes required by GAAP
for complete financial statements and allowed by the relevant SEC rules and regulations; however, the Company believes that its
disclosures are adequate to ensure that the information presented is not misleading. Certain amounts in prior periods have been
reclassified to conform to current presentation.&lt;/p&gt;

&lt;p style="font: 10pt/normal Times New Roman, Times, Serif; margin: 0; text-indent: 0.5in"&gt;&amp;#160;&lt;/p&gt;

&lt;p style="font: 10pt/normal Times New Roman, Times, Serif; margin: 0; text-align: justify; text-indent: 9pt"&gt;&amp;#160;On June 7, 2013,
the Company effected a 1-for-10 reverse stock split of its common stock. All share and per share information has been retroactively
restated to reflect this reverse stock split.&lt;/p&gt;

&lt;p style="font: 10pt/normal Times New Roman, Times, Serif; margin: 0"&gt;&amp;#160;&lt;/p&gt;

&lt;p style="font: 10pt/normal Times New Roman, Times, Serif; margin: 0; text-align: justify"&gt;&lt;b&gt;&lt;i&gt;&lt;u&gt;Liquidity and Management&amp;#146;s
Plans&lt;/u&gt;&lt;/i&gt;&lt;/b&gt;&lt;/p&gt;

&lt;p style="font: 10pt/normal Times New Roman, Times, Serif; margin: 0; text-indent: 0.5in"&gt;&amp;#160;&lt;/p&gt;

&lt;p style="font: 10pt/normal Times New Roman, Times, Serif; margin: 0; text-align: justify; text-indent: 9pt"&gt;&amp;#160;The accompanying
consolidated financial statements have been prepared on a basis assuming that the Company is a going concern, which contemplates
the realization of assets and the satisfaction of liabilities in the normal course of business.&amp;#160;&amp;#160;As of June 30, 2013,
the Company had cash of approximately $11,608,000, working capital of approximately $8,453,000, and an accumulated deficit of
approximately $104,232,000.&amp;#160;&amp;#160;The Company continues to incur recurring losses from operations.&amp;#160;&amp;#160;The Company
will require additional capital to fund our product development, research, manufacturing and clinical programs in accordance with
our current planned operations.&amp;#160;&amp;#160;Management intends to pursue additional financing to fund these operations and the
Company has funded its operations in the past primarily through debt and equity issuances.&amp;#160;&amp;#160;Management believes that
it will be successful in meeting the milestones required under their current financing arrangement and/or raising additional capital.&amp;#160;&amp;#160;No
assurances can be given that additional capital will be available on terms acceptable to the Company. The consolidated financial
statements do not include any adjustments that might result from the outcome of these uncertainties.&lt;/p&gt;</NonNumbericText><FootnoteIndexer /><CurrencyCode /><CurrencySymbol /><IsIndependantCurrency>false</IsIndependantCurrency><ShowCurrencySymbol>false</ShowCurrencySymbol><DisplayDateInUSFormat>false</DisplayDateInUSFormat></Cell></Cells><ElementDataType>nonnum:textBlockItemType</ElementDataType><SimpleDataType>na</SimpleDataType><ElementDefenition>The entire disclosure for organization, consolidation and basis of presentation of financial statements disclosure.</ElementDefenition><ElementReferences>Reference 1: http://www.xbrl.org/2003/role/presentationRef

 -Publisher FASB

 -Name Accounting Standards Codification

 -Topic 810

 -SubTopic 10

 -Section 50

 -Paragraph 8

 -URI http://asc.fasb.org/extlink&amp;oid=28200181&amp;loc=SL6228881-111685



Reference 2: http://www.xbrl.org/2003/role/presentationRef

 -Publisher FASB

 -Name Accounting Standards Codification

 -Topic 720

 -SubTopic 15

 -URI http://asc.fasb.org/subtopic&amp;trid=2122524



Reference 3: http://www.xbrl.org/2003/role/presentationRef

 -Publisher FASB

 -Name Accounting Standards Codification

 -Topic 205

 -SubTopic 10

 -Section 50

 -Paragraph 1

 -URI http://asc.fasb.org/extlink&amp;oid=6359566&amp;loc=d3e326-107755



Reference 4: http://www.xbrl.org/2003/role/presentationRef

 -Publisher FASB

 -Name Accounting Standards Codification

 -Topic 235

 -SubTopic 10

 -Section 50

 -Paragraph 3

 -URI http://asc.fasb.org/extlink&amp;oid=6367646&amp;loc=d3e18780-107790



Reference 5: http://www.xbrl.org/2003/role/presentationRef

 -Publisher FASB

 -Name Accounting Standards Codification

 -Topic 205

 -SubTopic 10

 -Section 45

 -Paragraph 3

 -URI http://asc.fasb.org/extlink&amp;oid=7668296&amp;loc=d3e288-107754



Reference 6: http://www.xbrl.org/2003/role/presentationRef

 -Publisher FASB

 -Name Accounting Standards Codification

 -Topic 810

 -SubTopic 10

 -URI http://asc.fasb.org/subtopic&amp;trid=2197480



Reference 7: http://www.xbrl.org/2003/role/presentationRef

 -Publisher FASB

 -Name Accounting Standards Codification

 -Topic 810

 -SubTopic 10

 -Section 50

 -Paragraph 1

 -URI http://asc.fasb.org/extlink&amp;oid=18733093&amp;loc=d3e5614-111684



Reference 8: http://www.xbrl.org/2003/role/presentationRef

 -Publisher FASB

 -Name Accounting Standards Codification

 -Topic 915

 -SubTopic 235

 -Section 50

 -Paragraph 1

 -URI http://asc.fasb.org/extlink&amp;oid=6472506&amp;loc=d3e38932-110933



Reference 9: http://www.xbrl.org/2003/role/presentationRef

 -Publisher FASB

 -Name Accounting Standards Codification

 -Topic 852

 -SubTopic 10

 -URI http://asc.fasb.org/subtopic&amp;trid=2209116



Reference 10: http://www.xbrl.org/2003/role/presentationRef

 -Publisher FASB

 -Name Accounting Standards Codification

 -Topic 272

 -SubTopic 10

 -Section 50

 -Paragraph 3

 -URI http://asc.fasb.org/extlink&amp;oid=6373374&amp;loc=d3e70478-108055



Reference 11: http://www.xbrl.org/2003/role/presentationRef

 -Publisher FASB

 -Name Accounting Standards Codification

 -Topic 275

 -SubTopic 10

 -URI http://asc.fasb.org/subtopic&amp;trid=2134480



Reference 12: http://www.xbrl.org/2003/role/presentationRef

 -Publisher FASB

 -Name Accounting Standards Codification

 -Topic 205

 -SubTopic 10

 -URI http://asc.fasb.org/subtopic&amp;trid=2122150



</ElementReferences><IsTotalLabel>false</IsTotalLabel><UnitID>0</UnitID><Label>Note 1. ORGANIZATION AND BASIS OF PRESENTATION</Label></Row></Rows><Footnotes /><IsEquityReport>false</IsEquityReport><ReportName>ORGANIZATION AND BASIS OF PRESENTATION</ReportName><MonetaryRoundingLevel>UnKnown</MonetaryRoundingLevel><SharesRoundingLevel>UnKnown</SharesRoundingLevel><PerShareRoundingLevel>UnKnown</PerShareRoundingLevel><ExchangeRateRoundingLevel>UnKnown</ExchangeRateRoundingLevel><HasCustomUnits>true</HasCustomUnits><IsEmbedReport>false</IsEmbedReport><IsMultiCurrency>false</IsMultiCurrency><ReportType>Sheet</ReportType><RoleURI>http://echotx.com/role/OrganizationAndBasisOfPresentation</RoleURI><NumberOfCols>1</NumberOfCols><NumberOfRows>2</NumberOfRows></InstanceReport>
