Abstract. The macrofaunas associated with the three morphologically different North Aegean Sea sponge species Agelas oroides, Aplysina aerophoba, and Axinella cannabina were compared. The faunal abundance was not related to sponge surface area for any of the three species. Each sponge species supported a significantly different number of individuals per unit canal volume; A. aerophoba supported the most, A. oroides the least. A. aerophoba supported the highest species richness, A. cannabina the lowest. Canal volume was a good predictor of associated faunal abundance and species richness for two of the three sponge species. Faunal abundance was also directly related to sponge mean canal diameter. The species composition of associated fauna was similar on A. aerophoba and A. oroides and significantly different on A. cannabina.