The effects of varying levels of dietary energy and protein on gross morphology and histology of testes of FUNNAB–Alpha chickens were studied at the Abubakar Tafawa Balewa University Bauchi, Bauchi state. Twelve cocks were randomly divided into four dietary treatments; Standard diet (SD)(Control)(2650Kcal/Kg ME/16% CP), High Energy–Low Protein (HELP, 2800 Kcal/Kg ME/14% CP), High Energy–High Protein (HEHP, 2800 Kcal/Kg ME/18% CP) and Low Energy–Low Protein (LEHP, 2400 Kcal/Kg ME/18% CP) groups. A total of twelve FUNAAB–Alpha cocks were used for this experiment. The cocks were reared in floor pens under natural mating. At 69 weeks of age, all the cocks were slaughtered and testicles carefully removed for gross morphology and histological studies. A significant (P< 0.05) influence of diet was noted on live weight with cocks fed HELP diet being heavier (P< 0.05) than those in the other treatment groups. Means for all parameters of testicles measured where not different (P> 0.05) from each other. Histological sections of the testes showed that HELP diet had mild effect on spermatogenesis evidenced by the scanty spermatozoa in the tubular lumen. It was concluded that FUNAAB–alpha cocks can be fed diets meant for breeding hens without adverse effect on spermatogenesis. However, feeding the LEHP diet produced roosters that were overweighed with slightly impaired spermatogenesis.