In addition to three new isolates, six strains of representative species of sulfate-reducing bacteria were tested for their capacity to use elemental sulfur as an electron acceptor for growth. There was good growth and sulfide production by strain Norway 4 and the three isolates, two of which had been enriched with sulfur flower and one isolated from a culture with green sulfur bacteria. Slow but definite growth was observed with Desulfovibrio gigas. The type of strains of Desulfovibrio desulfuricans, D. vulgaris, and Desulfotomaculum nigrificans as well as Desulfomanoas pigra did not grow with sulfur. The four strains that grew well with sulfur flower were straight, nonsporulating rods and did not contain desulfoviridin.