Aims: To compare growth of Lactobacillus plantarum on media containing hydrolysates ( peptones) from cod viscera with growth on commercial media. Methods and Results: Growth of Lact. plantarum on various fish peptones and commercial peptones/ extracts was evaluated using both a Bioscreen apparatus ( microtiter plates, no pH control) and fermentors ( with pH control). Generally, the performance of the fish peptones was good and only beaten by the performance of yeast extract. Replacement of the 22 g l(-1) complex nitrogen source in standard MRS medium with only 5 g l(-1) fish peptone reduced the biomass yield with only 10%, whereas replacement with a mixture of 2.5 g l(-1) fish peptone and 2.5 g l(-1) yeast extract increased the biomass yield by 10%. Conclusions: Peptones derived from cod viscera support excellent growth of Lact. plantarum. Significance and Impact of the Study: We show that peptones derived from cod viscera are promising constituents of growth media for fastidious food bacteria such as lactobacilli. Media containing these peptones show excellent performance while problems associated with the use of meat- derived peptones ( BSE, kosher status) or plant- derived peptones ( genetically modified organisms) are avoided.