A pure bromotyrosine derivative, psammaplin A, has been isolated from the sponge Druinella (Psammaplysilla) purpurea, collected from the Fijian Islands. The extracts were partitioned and separated by size exclusion chromatography on a Sephadex LH-20 column and further purified by reversed phase HPLC. The structures of the pure compounds were determined via interpretation of spectral data, mainly mass spectrometry, ¹H and ¹³C NMR, as well as comparison with the known psammaplins.