The effect of medium composition and initial glucose concentration on production of hEGF by recombinant E. coli cells was investigated. Optimum hEGF production was observed in a yeast extract/acid hydrolysed casein/salts media containing an initial glucose concentration of 10 g.l(-1). A maximum hEGF titer of 250 mg.l(-1) was obtained in this medium after 32 h in laboratory fermenters with pH, temperature, agitation and aeration set at 6.8, 30 degrees C, 500 rpm and 2 vym, respectively.