Photoxidation of palm oil, like other forms of oils/lipids oxidation has adverse effects on the physicochemical qualities of the oil including depletion of essential antioxidants and formation of free radicals which could be injurious to tissues. Unfortunately, this widely consumed edible vegetable oil is usually stored or displayed for sale in plastic containers under direct sun light and unknowingly subjecting the oil to photoxidation. This work therefore sought to evaluate the possible effect of long term consumption of palm oil exposed to light on some reproductive parameters in male wistar rats. Male wistar rats weighing 85g to 120g and aged 19 to 23 weeks were randomly divided into a control and photoxidised palm oil (PPO)-fed groups of five rats each. The control group was fed on normal rat chow while the PPO diet group was fed on photoxidized palm oil diet. The duration of feeding was 13 weeks after which the rats were euthanized, blood samples collected while testes were harvested from them for determination of relevant parameters. The result showed a significantly reduced seminal pH in the PPO-fed group compared with control (P<0.01). Sperm motility (%) and viability (%) were significantly decreased (P<0.01 and P<0.01 respectively) in the PPO-fed group compared with control. The PPO-fed group had significantly decreased (P<0.001) sperm count and a significantly increased percentage of morphologically defective sperm cells (p<0.05) compared to the control. Serum testosterone, follicle stimulating hormone (FSH) and Luteinizing hormone (LH) were significantly decreased (P<0.001, P<0.01 and P<0.001 respectively) in the PPO-fed rats compared with control. In conclusion, long term consumption of PPO diet impairs reproductive function in male wistar rats