The study was conducted to investigate the effects of supplementation of melamine in diets on growth performance and health of broilers. A single factor trial design was adopted, and a total of 375 one-day-old healthy Avian white feather broilers were randomly allotted to 5 groups with 5 replicates per group and 15 chicks per replicate. Broilers were fed with the corn-soybean meal basal diets with 0 (control group), 250, 500, 1 000, and 2 000 mg/kg melamine, respectively. The trial lasted for 43 d. On d 21 and 42, broilers were weighed, and average body weight gain (ABWG), average feed intake (AFI), and feed/gain (F/G) were calculated on the basis of a replicate. On d 22 and 43, broilers were sacrificed to take the samples of duodenum, kidney and blood. Blood samples were collected to analyze the contents of creatinine (CRE) and urea nitrogen (UN), and the activities of glutamic-pyruvic transaminase (GPT) and glutamic-oxaloacetic transaminase (GOT) in serum. Fresh samples of kidney and duodenum were evaluated via light microscopy. The results showed as follows: 1) there were no significant differences in AFI and ABGW among all groups (P>0.05), but there was a trend of decrease in ABGW of 1 000 and 2 000 mg/kg groups. The F/G of 1 000 mg/kg group was significantly higher than that of the control group on d 21 to 42 (P<0.05). 2) The activity of GOT in serum was significantly increased when the supplemental level of melamine was 500 mg/kg or higher (P<0.05), and the activity of GPT, the contents of urea nitrogen on d 22 and creatinine in serum were significantly increased (P<0.05). 3) The kidney and duodenum damages were severer with the increasing of melamine supplemental level when it was 250 mg/kg or higher. In conclusion, 1 000 mg/kg or more melamine inhibits the growth performance, while 250 mg/kg or more melamine damages the health of broilers, and the damages are exacerbated as melamine level increases.［Chinese Journal of Animal Nutrition, 2010，22（6）:1694-1702］