After our studies about the marine mollusks of St. Martin, (COOMANS 1963a, 1963b), this publication will deal with the land and freshwater shells of the island. The non-marine mollusks of St. Martin were already fairly well known at the end of the last century (MAZÉ 1890, p. 22—34), who mentioned 36 species, mainly collected by H. E. VAN RIJGERSMA. VERNHOUT (1914) compiled from the literature the land and freshwater mollusks of the Netherlands Antilles, and he listed 37 species from St. Martin (not including 12 brackish water species). VERNHOUT’S list was entirely copied by SCHEPMAN (1915). Many specific names have changed since 1914, and more collecting was done on St. Martin during the last decades. This publication will cover all the species of non-marine mollusks known to us from the literature, from museum collections, and from our own collecting on St. Martin. One new subspecies of Adamsiella crenulata is described and figured here.