The objective of this study was to peruse the annular variations in testicular histomorphology and serum testosterone of guinea fowl (Numida meleagris) during different reproductive phases viz., resting, progression and peak breeding in Pakistan. Thirty healthy male birds were slaughtered: samples of testes were stained with H&E and histometric analysis was made with Image J®. Serum testosterone was measured by radioimmunoassay. Results revealed significantly (P<0.01) greater values of weight, volume, length, width, thickness and circumference of testes during peak breeding as compared to other phases. Histometric parameters like diameter of seminiferous tubules and its lumen, thickness of germinal epithelium and diameter of leydig cells showed significantly (P<0.01) higher values during peak breeding than other phases. Conversely, thickness of testicular capsule and percentage area of interstitial cells were significantly (P<0.01) higher during resting in contrast to progression and peak phases. Serum testosterone showed significantly (P<0.01) higher value (4.60±0.44) during peak breeding which declined significantly (P<0.01) in progression (1.73±0.19) and resting (0.62±0.07) phases. Moreover, all histomorphometric changes were positively correlated while percentage area of interstitial cells and thickness of testicular capsule were negative with hormonal profile during each phase. In conclusion, different reproductive phases influence annular testicular histomorphology and hormonal profile. Peak breeding activity of this bird is coincided with the increased steroid hormone synthesis under suitable circumstances.