Sustained release of drugs from polymeric matrices has received increased interest. However, unitl now only a few examples are available where steroids are covalently bonded to a polymeric system and no data are available about the coupling of steroids to biodegradable polymers. This paper reports a new derivatization of 17 alpha -ethynyl-17 beta -hydroxy steroids, which is applicable for attachment to biodegradable poly( alpha -amino acids). Poly(hydroxyalkyl)-L-glutamines are prepared through base catalyzed polymerization of gamma -benzyl-L-glutamate N-carboxyanhydride giving the polymeric benzyl-L-glutamate, followed by displacement of the benzyl group with the desired hydroxyalkyl amines. The polymers are water soluble but upon substitution with hydrophobic steroids become water insoluble. Microparticles of the drug-polymer conjugate have been subcutaneously implanted in female rats. Liquid scintillation counting of urine and feces indicate that the contraceptive steroid is released in near zero order kinetics for more than 200 days.