To investigate whether formational properties of sign language are used spontaneously to organize long-term memory, 16 deaf college students were given a free recall task with items that could be categorized either by shared semantic category or by shared sign language hand shape. Both presentation and response modes (signed or written) were varied between subjects. Analyses revealed no effects of mode on trials to criterion or number of items recalled at 1 week. The clustering that occurred was exclusively semantic, with significantly higher clustering scores during acquisition trials in subjects required to sign their responses. In Experiment 2, formational clustering was encouraged by including formational similarity as the only experimenter-defined basis of categorization, by increasing formational similarity within categories, and by testing only subjects with high signing skills. Input and output modes were again varied between subjects. Subjects were deaf college students with deaf parents (n = 10) or hearing parents (n = 16), and hearing adults with deaf parents (n = 8). Again, spontaneous clustering by formational similarity was extremely low. In only one case— deaf subjects with hearing parents given signed input—did formational clustering increase significantly across the eight acquisition trials. After the categorical nature of the list was explained to subjects at a 1-week retention session, all groups clustered output by formational categories. Apparently, fluent signers do have knowledge of the formational structure of signs, but do not spontaneously use this knowledge as a basis of mnemonic organization in long-term memory.