The effect of lyophilized aqueous extract of Cynomorium coccineum and Withania somnifera on testicular development and on serum levels of testosterone, ICSH and FSH was studied in immature male Wistar rats. There was a notable increase in testicular weight of animals treated with both extracts. Histological examination revealed an apparent increase in the diameter of seminiferous tubules and the number of seminiferous tubular cell layers in the testes of treated rats as compared with control ones. Extracts of both plants elicited notable spermatogenesis in immature rats but C. coccineum was more effective than W. somnifera in that respect. Serum testosterone and FSH levels were lower in animals treated with plants extracts than controls, whereas ICSH levels was higher in treated animals, specially in those treated with C. coccineum. It was concluded that extracts of both plants have a direct spermatogenic influence on the seminiferous tubules of immature rats presumably by exerting a testosterone-like effect.