The toxic effects of Mucuna pruriens var utilis seeds on the kidney was evaluated on white albino Wistar rats in the laboratory using powdered raw and cooked Mucuna seeds incorporated into the feed of the rats at 10, 20 and 50% levels for four weeks, and than evaluating the serum urea and creatinine levels (kidney function tests) of the rats. The serum urea levels of the rats fed with different percentage inclusions of raw Mucuna seeds in the feed were significantly (P<0.001) increased in a dose dependent manner when compared to the negative control group. Also the serum urea and creatinine levels of the rats fed with different percentage inclusions of cooked Mucuna pruriens seed in the feed where significantly (P <0.02) increased when compared to the negative control group of the rats. These increased with the increase in the percentage inclusion in the feed. In conclusion, this study suggests that feeding Mucuna pruriens, var utilis seeds to animals or man may cause some levels of damage to the kidney which may be dependent on the level of inclusion in the feed and the toxic effect may also be drastically reduced by cooking the seeds before using it for feeding.