Eighty mature catfish of both sexes were used to study the effect of different seasons on the histological
and histochemical structure of the gonads. The results showed that winter season was considered as a resting season of the gonad of the catfish where the testes showed degeneration except intact spermatogonia and theovaries showed predominance of previtellogenic stage. Both of spring and summer seasons were considered as the spawning (breeding) season of the catfish where the testicular lobules became distended with the different developmental stages with the appearance of spermatozoa while the ovaries showed predominance of vitellogenic and postvitellogenic stage with the appearance of mature follicles. Autumn season was considered as the postspawning season where the testes showed some empty or spent testicular lobules while the ovaries had predominance of the atretic follicles which indicates the spawned fish.