This study was designed to determine the effect of seasonal and nutritional variation on puberty through testicular measurements and scrotum circumference  in sixteen Saidi ram lambs of 6-7 months of age (with average body weight 31.55 .kg). Animals were divided into four separate equal groups (four animals/group). The 1^st  group was fed a basal diet (BD), to which the other treated groups was compares the 2^nd   group was fed a high protein ration with a level of energy as of group 1  (HP), the 3^rd group was fed a high energy ration with a protein level as of group1 (HE) and the 4^th group was fed a high protein/high energy ration (HH). The main effects in this experiment were season and level of feeding. Ram lambs were checked daily early in the morning for 15 minutes for observing sexual behaviors by introducing a ram lamb to a teaser ewe chosen randomly from a flock of sheep. A ram which appeared erection and extrusion of the penis out of the sheath was caught immediately and a smear of fluids secreted around the penile sheath was prepared for microscopic examination. A ram which produced sperm in the smear was immediately taken to be trained for collection of seminal ejaculates by an artificial vagina. Rams fed HP ration reached puberty at an earlier time (338.3 days) than rams fed HE ration (349.0 days), rams fed HH ration (373.0 days) and rams fed a basal diet ration (BD) (394.5 days). Level of feeding had a significant effect on puberty. The higher measurements for the right and left testicular diameters occurred in summer and spring with averages of 6.02±0.04 cm, 6.02±0.04 cm, 6.02±0.07 cm and 5.98±0.07 cm, respectively. Rams fed high protein/high energy (HH  group) resulted in relatively higher diameters in both right (6.06±0.04 cm) and left (6.06±0.04 cm) testes than the other treated groups, while rams fed a basal diet (BD group) resulted in very low testicular diameters with average of 5.61±0.08 cm for both right and left testes. Season had a significant effect (p < 0.05) on testis diameter. The higher measures for the right and left testicular  length occurred in summer and autumn with averages of 7.99±0.07 cm, 7.98±0.07 cm, 8.00±0.08 cm and  8.00±0.08 cm, respectively. Moreover, the effect of feeding level and the interaction between season and level of feeding was statistically significant (p < 0.05) on the testicular length. Season effect was also found to be statistically significant (p < 0.05) on the scrotal circumference. Scrotum circumference value was much better in spring (31.32±0.24 cm) and summer (30.53±0.21 cm) than winter (29.58±0.23 cm) and autumn (29.44±0.23 cm). The effect of level of feeding and the interaction between level of feeding and season was  statistically significant (p < 0.05) on the scrotal circumference. Protein content of the diet is of important factor influencing growth and regression of the testes in  rams. From these data one may conclude that low levels of feeding are likely to be unacceptable in practice owing to reduction in age at puberty and semen quality as well. Testis measurements can be applied for assistance in the determination of  puberty.