Insulin like growth factor II (IGF-II) gene encoding pre pro-form of IGF-II was isolated from human adult liver cDNA libraries. Mature form of IGF-II were expressed using E. coli expression system under the control of Tac promoter. Mature form of IGF-II cDNA was fused with a truncated lacZ gene, so that the mature IGF-II protein was expressed as a fusion protein with β-galactosidase at C-terminus. In expressed cell lysate, galactosidase-IGF II fusion protein was about 30% of total cellular proteins. The fusion protein was formed as inclusion bodies. The inclusion bodies were purified and IGF-II protein was obtained by CNBr cleavage. The released IGF-II was confirmed by its molecular weight as determined by SDS-PAGE and its ability to bind to anti-IGF I antibodies.