<?xml version="1.0" encoding="UTF-8"?>
<edgarSubmission xmlns="http://www.sec.gov/edgar/seventeenafiler" xmlns:com="http://www.sec.gov/edgar/common">
  <headerData>
    <submissionType>X-17A-5</submissionType>
    <filerInfo>
      <filer>
        <filerCredentials>
          <filerCik>0001015257</filerCik>
          <filerCcc>XXXXXXXX</filerCcc>
        </filerCredentials>
      </filer>
      <liveTestFlag>LIVE</liveTestFlag>
      <flags>
        <returnCopyFlag>false</returnCopyFlag>
        <confirmingCopyFlag>false</confirmingCopyFlag>
        <overrideInternetFlag>false</overrideInternetFlag>
      </flags>
    </filerInfo>
  </headerData>
  <formData>
    <submissionInformation>
      <periodBegin>01-01-2025</periodBegin>
      <periodEnd>12-31-2025</periodEnd>
      <typeOfRegistrant>
        <typeOfBDRegistrant>Broker-dealer</typeOfBDRegistrant>
      </typeOfRegistrant>
      <materialWeakness>Y</materialWeakness>
    </submissionInformation>
    <registrantIdentification>
      <brokerDealerName>W.G. NIELSEN &amp; CO.</brokerDealerName>
      <businessAddress>
        <com:street1>3200 CHERRY CREEK DRIVE SOUTH</com:street1>
        <com:street2>SUITE 470</com:street2>
        <com:city>DENVER</com:city>
        <com:stateOrCountry>CO</com:stateOrCountry>
        <com:zipCode>80209</com:zipCode>
      </businessAddress>
      <contactPersonName>Teresa Crosier</contactPersonName>
      <contactPersonPhoneNumber>303-888-1512</contactPersonPhoneNumber>
    </registrantIdentification>
    <accountantIdentification>
      <accountantName>Haynie &amp; Company</accountantName>
      <accountantAddress>
        <com:street1>1785 West 2300 South</com:street1>
        <com:city>Salt Lake City</com:city>
        <com:stateOrCountry>UT</com:stateOrCountry>
        <com:zipCode>84119</com:zipCode>
      </accountantAddress>
      <accountantType>Certified Public Accountant</accountantType>
    </accountantIdentification>
    <oathSignature>
      <signPersonName>Teresa L. Crosier</signPersonName>
      <entityName>W.G. NIELSEN &amp; CO.</entityName>
      <signDate>12-31-2025</signDate>
      <signature>Teresa L. Crosier</signature>
      <oathTitle>CCO/Finop</oathTitle>
    </oathSignature>
  </formData>
</edgarSubmission>
