Epixanthus dentatus (Crustacea: Brachyura: Eriphiidae) is a predator crab, commonly inhabiting East African mangroves, whose nocturnal and elusive behaviour usually prevents analysis of its natural diet and prey selection. The present study was carried out on a population inhabiting a peculiar mangrove habitat in which E. dentatus produces heaps of non-ingested parts of its prey. Fifty-nine of these accumulations of prey remains were examined and 17 species were identified as part of the diet of E. dentatus. Relative prey consumption was then analysed with respect to the relative abundance of prey species within the local faunal community. This methodology provided important information about prey selection by E. dentatus; in particular, gastropods were always strongly under-represented, while there was an active selection among the different crab species. Uca species were under-represented, while swimming crabs were also part of the E. dentatus diet, which shows that the latter is able to prey both at low and high tide.