Saffron callus was grown in a two-stage culture on B5 medium supplemented with casein hydrolysate ( 300 mg l(-1)) at 22 degreesC in dark with naphthalene acetic acid (2 mg l(-1)) and 6-benzyladenine (1 mg l(-1)) to give maximum biomass (16 g dry wt l(-1)), and with indole 3-acetic acid (2 mg l(-1)) and 6-benzyladenine (0.5 mg l(-1)) for crocin formation. The maximum crocin production (0.43 g l(-1)) was achieved by this two-stage culture method, which was three times that by a one-stage method.