Fragments of HIV-1 structural proteins: gp120, gp41, p24, p17 were expressed in E. coli as fusion proteins with N-end fragment of b-galactosidase. To extract the virus fragments from fusion proteins with the use of acid hydrolise, acid-labile bonds Asp-Pro were added at the point of junction. An original method of isolation and purification of inclusion bodies from E. coli cells was developed. The virus peptides obtained were homogeneous on SDS PAGE. These peptides showed no reaction with anti-E. coli antibodies on Western blot test. The level of endotoxin was very low. The obtained virus peptides had strong, antigenic specifity good enough to be used to construct a diagnostic test for the detection of anti-HIV antibodies, that could be used in clinical and scientific research.