A halophilic endospore-forming, sulfate-reducing bacterium was isolated from an oilfield brine in France. The strain, designated SEBR 3139, was composed of long, straight to curved rods. It grew in 1-14% NaCl with an optimum at 6%. On the basis of morphological, physiological and phylogenetical characteristics, strain SEBR 3139 should be classified in the genus Desulfotomaculum. However, it is sufficiently different from the hitherto described Desulfotomaculum species to be considered as a new species. Strain SEBR 3139T (= DSM 11559T) represents the first moderate halophilic species of the genus Desulfotomaculum. The name Desulfotomaculum halophilum sp. nov. is proposed.