Steroid genesis is regulated by several enzymes. P450c17 is the single enzyme mediating both 17α-hydroxylase and 17,20lyase activities in the synthesis of steroid hormones. P450c17 is a universal enzyme which converts progesterone and pregnenolone to their 17α-hydroxylated products, and then to Dehydroepiandrosterone (DHEA) and androstenedione respectively P450c17 is needed for final maturation of oocytes, which is necessary for fertilization. Present attempt made to find out the expression of Cyp17 mRNA of different region of brain in the Cirrhinus mrigala. The gene was observed by PCR amplification with a specific primer for Cyp17. Our results confirm the presence of the gene cyp17 that codes for the enzyme p450c17 in the various regions of brain of an Indian major carp, especially C. mrigala by catalyzing the gene expression through PCR techniques. The further study was require to analyse characterization of Cyp17 gene in these fish species along with different classes of vertebrates and with fishes to know its similarity, evolutionary distance and relationship with other organisms.