The nucleoside, 9~-(2deoxy-~-ribofnosyl)-2-methoxyadenine [2), previously unknown as a natural product, has been isolated from a sponge in addition to the known nucleoside 9P-~-ribofuranosyl-2-methoxyadenine (spongosine) 111. Thymine and 2 methoxyadenosine were also isolated from this sponge as a mixture. Nucleosides with biological activity have been isolated from a variety of marine sources (1,2). The potent antifungal activity demonstrated by toyocamycin (3,4) prompted our investigation of nucleosides from sponges. We have examined a sponge collected from Western Australia, and have isolated two nucleosides, spongosine {I], originally reported by Bergmann from Cryptotetbya cvypta (Hadromerida) (5-7), and 2'-deoxyspongosine [2}. Compound 2 has previously been obtained as a synthetic product @), but this is the first report of it as a natural product. We also present herein completely assigned nmr spectral data for both 1 and 2 for the first time.