The results of long-term studies of the species composition of benthic diatoms in Laspinskaya Bay of the Crimean coast of the Black Sea are summarized. The epiphyton, consisting of 18 species of macroalgae and one seagrass species Zostera marina, as well as the epilithon of rocks and pebbles, were studied. A checklist of Bacillariophyta was compiled, including 91 species and an intraspecific taxon belonging to 3 classes, 18 orders, 27 families, and 46 genera. Among them, 3 species are new to the Crimean coast of the Black Sea: Campylopyxis garkeana, Mastogloia pusilla var. subcapitata, and Seminavis cf. barbara. The most diverse genera were identified: Nitzschia (10 species), Navicula (9), Licmophora and Cocconeis (5 each). The epiphyton on macrophytes amounted to 86 taxa, of which the greatest number occurred on the brown alga Ericaria crinita (43) and the smallest number on the red alga Ceramium virgatum (9). The epilithon was represented by 44 species, 39 of them on rocks and 15 on pebbles. There were 13 frequently occurring species. The ecological and phytogeographic characteristics are indicated for each taxon. Benthic (84 %), marine (57 %), and cosmopolitan (37 %) forms dominated. The communities featured 46 indicator species of organic water pollution, with the leading position among them occupied by the beta-mesosaprobiotic group (48 %).