The genera Diplomphalus Crosse & Fischer, 1872 and Pseudomphalus Ancey, 1882 from New Caledonia are revised based on extensive new samples. Three Diplomphalus species occur on the main island of New Caledonia. Diplomphalus mariei (Crosse, 1867) is characterised by a callus which forms an arcuate lamella that projects from ofthe body whorl. Helix seberti Marie, 1881 and Diplomphalus fischeri Franc, 1953 are placed in the synonymy of D. mariei. Diplomphalus solidulaTryon, 1885 is separated from D. mariei for the first time as a distinct species. It differs in its callus being only slightly detached from the body whorl at its margin. Diplomphalus vaysseti (Marie, 1871) differs from D. solidula and D. mariei in possessing a weak callus which is not detached from the body whorl. Helix volutella Gassies, 1858 (not L. Pfeiffer, 1856) is placed in the synonymy of D. vaysseti. The two species from the Île Art (Îles Belep), Diplomphalus cabriti (Gassies, 1863) and Diplomphalus montrouzieri (Souverbie, 1858), differ from the species ofthe main island in their larger size. Relative to D. cabriti, D. montrouzieri is smaller and whitish without a brownish pattern and has weaker sculpture on the teleoconch. Pseudomphalus megei (Lambert, 1873) differs from the Diplomphalus species in its larger shell with rounded, widely overlapping whorls, a weaker sculpture and a narrower umbilicus and a short penis with a large conic flagellum and a fusiform vas deferens. Diplomphalus fabrei Crosse, 1875 is placed in the synonymy of P. megei. The distribution of all species is shown on maps.