In this study, the breeding biology of the lizard Agama stellio stellio was investigated. Adult testis weight changes markedly during the year, reaching maximum size in spring and minimum in summer. Seminiferous tubule diameter has its maximum level in spring and minimum in summer. Spermatogenesis is initiated in mid August and terminated in early July. Spermiogenesis is generally restricted to the period following hibernation. In July and August there is a complete spermatogenetic stasis. Epididymal tubules have their maximum diameter and epithelial cell height in spring. They are secretory during this season.