Two proteins (putative receptors) of 60 and 38 kDa, for chikungunya (CHIK) virus were detected in the brush border membrane fraction (BBMF) of the normal population of Aedes aegypti mosquitoes. Mosquitoes were infected orally with CHIK virus and infectivity checked by testing the head squashes. BBMF was prepared from proved positive and negative mosquitoes. The receptor proteins were found to be present in both the proved genotypes. However, dot-b'ot assays showed that the CHIK virus binding activity of BBMF/mg protein was noticeably low in the proved negative mosquitoes as compared to the positives. BBMF from the larvae of the normal populations also showed the presence of the receptor proteins, binding to CHIK virus. Receptor proteins from larvae as well as the adults were found glycosylated. CHIK virus receptor proteins of 24, 45, 58, 60 and 62 kDa were also seen in the membrane fraction of the C6/36 cells.