Microbial transformations of various steroids are reviewed. Developmen
tal studies on immobilization of microbial cells, techniques for selec
tive transformation and better yields of desired metabolites are highl
ighted. The present position of microbial biotechnology in the steroid
drug industry and the future prospects are discussed. Various steroid
substrates, their metabolites and the micro-organisms used for the tr
ansformations are compiled covering the literature for the period late
1987-mid 1992.