Abstract: Gout syndrome is one of the common mortality causes accounted for poultry farms. Gout is diagnosed by deposition of urates in kidney, on heart serous surfaces, liver, mesenteric, air sac and peritoneum, etc. There are two types of diseases: visceral and joint gout. Incidence of gout syndrome in broiler chicks increases mortality and decreases performance. Gout causing factors could be classified in three sections; management and nutritional factors, infectious factors and toxic factors. The current study conducted to evaluate effect of dietary calcium percentage on incidence of gout syndrome and its effect on serum biochemical parameters in broiler chicks. Total 300 broiler chicks (Ross 308), divided in two groups; treatment and control. Each group has three replicates (50). All management factors including: light (intense and duration), temperature, vaccination program, ventilation rate, nutrition, stocking density for both groups were same but dietary calcium percentage was different. Dietary calcium for treatment group was 2 and 1% in control group. Blood samples of each group were collected on 5th, 35th and 42nd days and their serum separated by centrifuging followed by biochemical parameters were measured. Serum biochemical parameters are uric acid, urea, total protein, albumin, creatinine, calcium, phosphorus, magnesium, alkaline phosphatase. In addition, macroscopic examination of renal necropsy, diet exchange ratio, mortality percentage and their relationship were evaluated in this study. Results showed that in treatment group the rate of uric acid, urea, total protein, albumin, creatinine, calcium, calcium and alkaline phosphatase have meaningful changes compared control with group (p<0.05). Evaluation of the serum level phosphorus in treatment group did reveal statistically significant decrease compared with control group (p<0.05). There was no statistical meaningful change in serum level magnesium between two groups (p>0.05). The FCR and mortality rate of treatment groups was higher than the control group. Deposition of urates in kidney, on heart serous surfaces, liver, mesenteric, air sac and peritoneum were displayed in treatment group. The urinary system of the treatment birds, in general, displayed inflammatory lesions showing abnormalities of color, size, shape and texture of kidneys and ureters. The ureters also showed occlusion and distention.