Various defined and minimal media are described for the growth of Clostridium sporogenes NCIB 8053. The organism requires 10 amino acids and one vitamin for growth, whilst three other vitamins are growth stimulatory. L-alpha-hydroxy acid analogues can replace eight, and fatty acid analogues four, of these amino acids. The organism may generate free energy by a variety of Stickland reactions. Most Stickland acceptors, but not glycine, stimulate the growth of this organism on glucose. Nonetheless, cells grown in the presence of glycine will reductively deaminate it. The media described support the growth of several other strains of this species. The simplified growth media which we have developed permit quantitative studies of the physiology of this organism.