In this paper, we summarize the diversity of Polyphysaceae species in Todos os Santos Bay, in the state of Bahia, Brazil. On the basis of ten years of collections and the analysis of herbarium material, six species have been recorded for the area: Acetabularia caliculus J.V.Lamour. in Quoy & Gaimard; A. crenulata J.V.Lamour.; A. schenckii Möbius; Parvocaulis myriosporus (Joly & Cord.-Mar.) C.W.N.Moura & J.C.De Andrade comb. nov.; P. pusillus (M.Howe) Berger et al.; and P. parvulus (Solms) S. Berger et al. The last has a distribution extending to the southern Atlantic Ocean. Acetabularia myriospora was transferred to Parvocaulis (as P. myriosporus) on the basis of its short corrugated peduncles and lack of a lower corona in the gametangial ray discs, which are diagnostic characters of this genus. In Todos os Santos Bay, Acetabularia species are more widely distributed than are Parvocaulis species, which are currently restricted to Itaparica Island. The most common taxa were A. caliculus and A. schenckii, which were collected from the majority of the study sites. This paper provides detailed descriptions of the morphology, reproductive aspects and geographic distributions of the algae, as well as discussing the taxa studied.