A detailed analysis of the secondary metabolites of Aplysina aerophoba and Aplysina cavernicola has been performed. A number of bromotyrosine derivatives have been identified of which two, 14 and 15, both isolated from A. cavernicola, are novel compounds. Their structures have been assigned on the basis of spectroscopic and chemical data. The obtained results indicate a remarkable difference in the secondary metabolism of the two sponges, which eventually confirms the separation of the two Mediterranean Aplysina species, in perfect agreement with Vacelet's opinion.