A simple synthetic medium with glycine,l-tryptophan anddl-alanine was developed for study of antimycin A biogenesis. The strain produced 550 mg of mycelium dry weight and 200 μg of antimycin A per 100 ml of this medium. Intense biosynthesis of antibiotic was initiated in early fermentation and optimum yields were achieved after an additional 96 h incubation. No absolute relationship between growth rate and antimycin A production intensity was found. Biogenesis of antimycin A via tryptophan and formylkynurenine is suggested and similarity in early biogenesis of both antimycin A and actinomycin is considered.