The use of pesticides is increasing rapidly as a result of vector-borne diseases and modern agriculture, which harm human beings, the environment, and wildlife including birds. The diversity of birds’ species to be a global decline. Pesticide contamination is a significant contributing factor to these declines, it is imperative to take this possibility into consideration. Birds are significant economically because they are the most valuable source of food and a vital component of the ecosystem. Therefore, the goal of the current study was to assess the testicular toxicity of organophosphate insecticide in pigeons. In order to assess the level of toxicity, eighty (80) healthy male Pigeons (Columba Livia domestica) were kept in neat and clean wooden cages. Throughout the experimental study a mixture containing 22% crude proteins and equal quantity of water were given to every pigeon. After acclimatization for fifteen (15) days pigeons were assigned in four equal groups (A, B, C, and D). For 84 consecutive days, each insecticide test group received oral doses of 1/25th, 1/20th, and 1/15th of the LD50 (1.3 mg, 1.6 mg, and 2.1 mg/kg body weight/day) of chlorpyrifos (CPF), while group (A) pigeons serving as the control. Birds from groups B, C, and D in this study exhibited significant clinical signs during the experimental study, including reduced food intake, tremors, salivation, open mouth breathing, ruffled feathers, lethargy, obvious depressive and dull symptoms, isolation, a decline in mating frequency, and watery diarrhea. The birds in the C and D groups shown a highly significant (P<0.01) decrease in body weights after exposure to CPF, while the B group observed with a significantly (P<0.05) decrease in body weight when compared to the birds in the control group. The testicular weights of the B, C, and D groups showed a highly significant (P<0.01) decrease due to the harmful effects of chlorpyrifos. At low dose of chlorpyrifos, the testes of group B pigeons showed condensed seminiferous tubules with empty lumens. The birds in the C and D groups showed hypertrophy/tumor between interstitial spaces, no spermatogonia, absence of Leydig's cells, and vacuolation in the tubules. The chlorpyrifos insecticide induced alerations in testicular histology of pigeons. The eco-toxicological risks of CPF insecticide to birds and other non-target organisms are evaluated, however, current research has shown that the chlorpyrifos insecticide has produced toxic effects on pigeons' male reproductive organs.