The study describes the steps of spermiogenesis and stages of seminiferous epithelial cycle in breeding guinea cocks. Sections embedded in epoxy resin were employed for the determination of the stages of seminiferous epithelial cycle in the guinea fowl. Acrosomic granules aided in identifying the initial steps of spermiogenesis, whereas nuclear morphological changes facilitated the identification of subsequent stages. Eleven steps of spermiogenesis and nine stages of seminiferous epithelium were recognized in the guinea fowl testis. Three spermatogonial types, namely, spermatogonial A, B and intermediate were identified in the guinea fowl seminiferous epithelium. Spermatogonial A and preleptotene spermatocytes had the largest (P < 0.05) nuclei diameters in the seminiferous epithelium, whereas round spermatids had the least. Within germ cells, no significant (P > 0.05) differences were found among birds in spermatogonial A and intermediate spermatogonial nuclei diameters. Spermatogonial B, preleptotene primary spermatocyte, type I spermatocyte (primary spermatocyte in prophase I), and round spermatid nuclei diameters were, however, bigger (P < 0.05) in some birds than others. The classification of the seminiferous epithelial cycle in the guinea fowl was similar to that described in other birds and mammals.