The present study reports the biotransformation of an anabolic-androgenic steroid (AAS) drostanolone heptanoate ( 1 ) by using two microbial cultures, Beauveria bassiana , and Macrophomina phaseolina . Fermentation of 1 with B. bassiana yielded five new transformed products 2–6 , while with M. phaseolina it afforded two new 7–8 , and two known 9–10 metabolites. The main sites of hydroxylation in the steroidal skeleton of 1 were at C-5, C-7, C-11, C-14, C-15, and C-20, hydrolysis of the ester moiety at C-17, and reduction of the carbonyl group at C-3. The structures of the transformed products were determined by using mass, NMR, and other spectroscopic techniques. This article is Open Access Please wait while we load your content... Something went wrong. Try again?