<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0306</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2023-01-23</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001287865</issuerCik>
        <issuerName>MEDICAL PROPERTIES TRUST INC</issuerName>
        <issuerTradingSymbol>MPW</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001331608</rptOwnerCik>
            <rptOwnerName>Aldag Edward K JR</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>1000 URBAN CENTER DRIVE</rptOwnerStreet1>
            <rptOwnerStreet2>SUITE 501</rptOwnerStreet2>
            <rptOwnerCity>BIRMINGHAM</rptOwnerCity>
            <rptOwnerState>AL</rptOwnerState>
            <rptOwnerZipCode>35242</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>Chairman, President &amp; CEO</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common stock, par value $0.001</value>
            </securityTitle>
            <transactionDate>
                <value>2023-01-23</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>320755</value>
                    <footnoteId id="F1"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>3753808</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common stock, par value $0.001</value>
            </securityTitle>
            <transactionDate>
                <value>2023-01-23</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>622642</value>
                    <footnoteId id="F2"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
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                <sharesOwnedFollowingTransaction>
                    <value>4376450</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common stock, par value $0.001</value>
            </securityTitle>
            <transactionDate>
                <value>2023-01-25</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
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                <value></value>
            </transactionTimeliness>
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                <transactionShares>
                    <value>115282</value>
                    <footnoteId id="F3"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
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                <sharesOwnedFollowingTransaction>
                    <value>4491732</value>
                </sharesOwnedFollowingTransaction>
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            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
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        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common stock, par value $0.001</value>
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            <transactionDate>
                <value>2023-01-25</value>
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                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
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                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>60965</value>
                    <footnoteId id="F4"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
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                <sharesOwnedFollowingTransaction>
                    <value>4552697</value>
                </sharesOwnedFollowingTransaction>
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                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common stock, par value $0.001</value>
            </securityTitle>
            <transactionDate>
                <value>2023-01-25</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>F</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
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            <transactionTimeliness>
                <value></value>
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            <transactionAmounts>
                <transactionShares>
                    <value>230003</value>
                    <footnoteId id="F5"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>11.14</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
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            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>4322694</value>
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            <ownershipNature>
                <directOrIndirectOwnership>
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    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">Shares vest ratably at the beginning of each of the 12 calendar quarters beginning April 1, 2023.</footnote>
        <footnote id="F2">Shares will be earned based on the achievement of specific performance thresholds pertaining to the Company's EBITDA and strategic transactions, as defined and set by our compensation committee, over the period from January 1, 2023 through December 31, 2025, with the opportunity to earn up to one third of the award for 2023 performance against the specified measures. The actual number of shares to be issued will vary depending upon the achievement of these specific performance thresholds and further adjusted pursuant to modifier provisions in the award that are based on the Company's total return to shareholders.</footnote>
        <footnote id="F3">Represents additional shares earned under the 2020 performance award based on the Company's actual performance as compared to the performance hurdles defined in the award agreement, adjusted pursuant to the modifier provisions in the award that were based on the Company's total return to shareholders. The shares vested in January 2023.</footnote>
        <footnote id="F4">Represents additional shares earned under the 2022 performance award based on the Company's actual performance as compared to the performance hurdles defined in the award agreement, adjusted pursuant to the modifier provisions in the award that were based on the Company's total return to shareholders. The shares vested in January 2023.</footnote>
        <footnote id="F5">Represents shares withheld upon vesting of restricted stock to satisfy tax withholding obligations. This does not constitute a sale transaction.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>W. Zachary Riddle, by power of attorney</signatureName>
        <signatureDate>2023-01-25</signatureDate>
    </ownerSignature>
</ownershipDocument>
