Pagurus longicarpus readily removes small prey (Artemia nauplii) from suspension under laboratory conditions. In our experiments, clearance rates of recently hatched nauplii were equal for male and female crabs and for crabs within or removed from their gastropod shells. Most feeding trials were performed with shell-less crabs. Crabs fed more effectively on nauplii in water of ambient salinity (30‰) than at 15‰. Feeding was more efficient between 20° and 30°C than at lower temperatures and was equally efficient in the light or dark. Rates of nauplii consumption were positively correlated with crab length. At concentrations of 4 nauplii/ml, crabs removed approximately 40% and 60% from suspension in 5 and 10 minutes, respectively. Nauplii were cleared more rapidly at higher concentrations. First zoeae of the brachyurans Dyspanopeus sayi and Carcinus maenas were readily removed from suspension by Pagurus longicarpus, but at lower rates than the smaller Artemia nauplii. The relatively large first zoeae of Palaemonetes vulgaris also were removed from suspension; in this case the crabs used their chelipeds to capture the zoeae. Up to 35% of recently hatched veligers of the gastropod Crepidula plana, the smallest prey species, were removed in 5-minute trials. The stomachs of crabs collected in the field contained what appeared to be a benthic diet of detritus but with some evidence of crustacean fragments that could have been derived from suspension. The mouth parts of P. longicarpus are not specialized for suspension feeding as in some species of hermit crabs. The activities of these mouth parts in conjunction with movements of the chelipeds and anterior walking legs combine to produce eddy currents around the head bringing suspended prey to the vicinity of the outer mouth parts where prey are grasped and ingested. Although the potential for active and efficient suspension feeding has been demonstrated, further observations are required to evaluate its importance in the crabs' natural habitat.