To study the signaling effect of insulin-like growth factor-Ⅰ(IGF-1), transgenic mice containing IGF-1 Receptor (IGF-1R) cDNA fused to metallothionein promoter were produced by DNA microinjection into the pronucleus of mouse zygote. Three founders were produced with transgenic mice containing IGF-1R gene. Transgenic mice lines contained approximately 4～20 copies of transgenes per cell and transmission of this gene into the progeny with Mendelian manner were determined. The founder mice were mated with normal mice to produce F1 mice and then F2 mice. Transmission rates of IGF-1R transgene in the progeny mice were 25～60% in F1 generation and 40～50% in F2 generation. The mRNA expression of IGF-1R transgene in liver was analyzed using RT-PCR for IGF-1R gene in liver. When body weights of transgenic pups were measured during 4, 10 and 14 weeks after birth, IGF-1R transgenic mice grew faster than non transgenic littermates. This study indicated that growth regulation by IGF-1 signaling through IGF-1R can be elucidated using IGF-1R transgenic mice.