The experiment was conducted to study the effects of melamine on growth performance, serum biochemical parameters and the toxicity in liver and kidney of broilers. A total of 1 920 one-day-old Cobb broilers were randomly allotted to 6 treatments (10 replicates per treatment and 32 chicks per replicate). Broilers in different treatments were fed with diets containing 0, 2, 10, 30, 50 and 100 mg/kg melamine. The experiment lasted for 42 days. The results showed that dietary melamine supplementation had no significant effects on the growth performance of broilers (P>0.05). At d 21, the serum glutamic-pyruvic transaminase (GPT) activity were increased with the increase of the melamine, and that of 100 mg/kg group was significantly higher than that of the control, 2, 10 and 30 mg/kg groups (P＜0.05). The serum uric acid (UA) content of 100 mg/kg group was significantly increased than that of 10 and 50 mg/kg groups at 21 d and the control, 2, 30 mg/kg groups at 42 d (P＜0.05); there were no significant differences in serum glutamic-oxaloacetic transaminase (GOT) activity and creatinine (CRE) content among all treatments (P＞0.05). The extent of damage of kidney and liver were increased with the increase of dietary melamine supplemental level. In conclusion, the diets supplemented with 0～100 mg/kg melamine have no significant effects on growth performance, but showed toxicity in the liver and kidney. The serum GPT activity and UA content are sensitive to dietary melamine supplementation. In the experiment, the toxicity of 100 mg/kg melamine is the strongest. ［Chinese Journal of Animal Nutrition，2011，23（1）：122-129］