Three new bromotyrosine alkaloids, purealidins E [1], F [2], and G [3], have been isolated from the Okinawan marine sponge Psammaplysilla purea and the structures elucidated on the basis of spectroscopic data. A number of bromotyrosine-derived alkaloids have been isolated from marine sponges, many of which belong to the family Verongidae (1). We have isolated several bioactive bromotyrosine alkaloids such as purealin (2), lipopurealins A-C (3), and purealidins A-D (4-6) from the Okinawan marine sponge Psammaplysilla purea Carter. Purealin in particular proved to be a useful tool for studying regulatory mechanisms of myosin K+, EDTA-ATPase or Na+,K+-ATPase (7). During our continuing investigations on bioactive substances from Okinawan marine organisms (8-11), extracts of P. purea were further examined to obtain three other biogenetically related compounds, purealidins E [1], F [2], and G [3]. In this paper we describe the isolation and structural elucidation of 1-3.