The genus Leucosyrinx Dall, 1889 is one of the highly diverse genera of the familyPseudomelatomidae, distributed across the Atlantic and Pacific Oceans. It remains poorly defined basedon conchological characters. The last revision of the genus was published by Powell (1969; Indo-PacificMollusca 2 (10): 207–415), in which many species were erroneously included, while others belongingto Leucosyrinx were attributed to different genera. For the first time, we have revised the Indo-Pacificspecies of the genus within the framework of integrative taxonomy, utilizing molecular-grade materialaccumulated in the Muséum national d’Histoire naturelle, France. Molecular phylogenetic analysisrevealed the existence of 62 secondary species hypotheses (SSHs) in our material, with 12 of themcorresponding to already named species. The remaining 50 SSHs represent new species, of which 24are described here, while 26 remain unnamed due to insufficient material. We refined the morphologicalcharacteristics of Leucosyrinx based on shell analysis of sequenced species from the genus, as well asfrom similar genera, particularly Comitas, Sibogasyrinx, and Comispira (the latter two belonging toCochlespiridae). This allowed us to assign 18 previously named species to Leucosyrinx, and conditionallyattribute four more, bringing the total number of species in the Indo-Pacific to 84, of which 58 are named.Numerous cases of cryptic species, which are nearly indistinguishable morphologically, were recordedwithin Leucosyrinx. The genus is confined to the upper bathyal zone, ranging from 195 to 1634 m indepth, with most occurrences between 500 and 1000 m. The highest species richness (30 species) wasrecorded in Papua New Guinea and the Solomon Islands, though this is likely due to more intensivesampling of the upper bathyal zone in these regions compared to other areas of the Indo-Pacific.