Sea urchins were collected in August 1999, at Salvador (Todos os Santos Bay, State of Bahia, Brazil). Twenty out of 20 Eucidaris tribuloides sea urchins studied had sponge remains in their guts, 12 of which, in large enough quantities to discard the hypothesis of sponge contamination on other food items. No other macroscopic evidence of alternative food sources has been encountered. Sponges found in large enough quantities were classified in seven genera, spread over seven families and five orders of the Demospongiae. Among the commonest sponges were Haliclona spp. and Iotrochota birotulata. The results show clearly the spongivorous habit of E. tribuloides at the studied site.