The distributions of fifteen species of macroscopic crustaceans living in non-marine and estuarine environments in Belgium are discussed. The species in question are: the conchostracan Leptestheria dahalacensis, the amphipods Gammarus tigrinus, Echinogammarus berilloni, Dikerogammarus villosus, Corophium curvispinum, Crangonyx pseudogracilis and Orchestia cavimana, the atyid shrimp Atyaephyra desmaresti, the crayfish Astacus leptodactylus, Pacifastacus leniusculus and Orconectes limosus and the crabs Callinectes sapidus, Eriocheir sinensis and Rhithropanopeus harrisii