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

    <schemaVersion>X0101</schemaVersion>

    <submissionType>EFFECT</submissionType>

    <act>33</act>

    <testOrLive>LIVE</testOrLive>

    <effectiveData>
        <finalEffectivenessDispDate>2010-05-20</finalEffectivenessDispDate>
        <finalEffectivenessDispTime>16:00:00</finalEffectivenessDispTime>
        <form>S-3</form>
        <filer>
            <cik>0001344413</cik>
            <entityName>Alexza Pharmaceuticals Inc.</entityName>
            <fileNumber>333-166514</fileNumber>
        </filer>
    </effectiveData>
</edgarSubmission>
