The production of several high value steroid drugs, used as progestational, adrenocortical, estrogenic and contraceptive agents, is mostly derived from 4-androstene-dione (AD) and 1,4 androsta-diene-3,17-dione (ADD). Three Vietnamese phytosterols mixtures named VN-1, VN-2 and VN-3, isolated from soybean oil may be efficiently converted into these key compounds by mycobacterial cells. Their general phytosterol composition was 55.39, 70.55, 70.19% for VN-1, VN-2 and VN-3, respectively. Moreover, values of campesterol, beta-sitosterol and stigmasterol were determined. After 120 h of shaking in suitable culture media and temperature, maximal yield conversion to ADD was higher than 70% and up to 64% to AD, for the various phytosterols mixtures assays. These results may be better when scaling-up such a procedure of phytosterols conversion.