Sex steroid hormones in mammals have shown to be synthesized not only in gonads but also in non-steroidogenic organs such as the brain. Steroid hormones in the brain were indicated to be involved in sex behavior and brain differentiation. In avian species, an experimental injection of androgen into the brain suggested the existence of a steroidogenic pathway. However, no studies have demonstrated the expression of genes involved in such a steroidogenic pathway in the brain, or in other non-steroidogenic organs of birds such as the liver and kidney. In this study, we have modified the RT-PCR procedure to analyze the expression of the steroidogenic genes, P-450scc, 3beta-HSD, P-450c17, 17beta-HSD and P-450arom in non-steroidogenic organs of chicken including the brain. The RT-PCR has demonstrated the presence of mRNAs from genes in non-steroidogenic as well as steroidogenic organs of chicken. The amounts of mRNAs from these genes (except for P-450c17) among the non-steroidogenic organs were found to be greatest in the brain.