The effect of supplementary nutrients on neomycin production was studied using Streptomyces marinensis NUV-5 in solid-state fermentation. Dextrin, raspberry seed powder, and concentrated mineral medium produced high neomycin yields and were selected for optimization. A full factorial composite experimental design and response surface methodology were used in the design of experiments and in the analysis of results. The maximum productivity of antibiotic under optimum conditions was 17150 mg kg(-1) of wheat rawa. The optimum conditions were dextrin 14.1 g kg(-1) rawa, raspberry seed powder 64.91 g kg(-1) rawa, and mineral salt solution 172.6 ml kg(-1) rawa. This method was efficient; only 20 experiments were necessary to assess these conditions and model adequacy was very satisfactory, as the coefficient of determination was 0.9560. (C) 2003 Published by Elsevier Science Ltd.