In southeastern Brazil, decapod crustaceans were found living in association with the scyphozoan jellyfish. In total, 2002 specimens of the Scyphozoa Lychnorhiza lucerna were collected of which 511 were associated decapods that were identified as three species of the crab Libinia ferreirae, Libinia spinosa, and one Grapsoidea sp. and two species of caridean shrimps Periclimenes paivai and Leander paulensis. This is the first record of an association between the caridean shrimp L. paulensis and a scyphozoan and the first report of symbioses involving the crabs L. spinosa and Grapsoidea sp. on the Brazilian coast.