Background: Colorectal cancer is the third most common non-cutaneous malignancy, and accounts for the second most frequent cause in cancer-related deaths. Early detection and diagnosis of cancer rectum and its metastasis is very helpful in treatment and prognosis ,so that  accurate laboratory markers have been needed to monitoring tumor recurrence, metastasis, and prognosis. Aim: The aim of this study was to investigate the role of uric acid (UA) in assessing rectal cancer metastasis. Patients and methods: Two hundred newly diagnosed patients with cancer rectum were included in our study and divided into two groups, one with metastasis and the other without metastasis. Results: There were statistical significant differences regarding CA19.9, carcino-embryonic antigen (CEA), and C-reactive protein (CRP) between the 2 groups. Importantly, serum concentrations of UA in patients with lymphatic metastasis were found to be increased compared with those without metastasis (7.08±2.45 vs 4.30±1.12; P<0.0001). There were positive correlations between serum UA and CRP, CA199 and CEA (r=0.27,P=0.0001; r=0.28,P=0.0001; r=0.29,P=0.0001) in rectal cancer patients with metastasis. Multivariate analysis model revealed that CEA, CA19.9 , CRP, ESR ( 1st , 2nd hours) ,serum uric acid, presence of ascites, Perirectal fat plane ,Degree of tumor  differentiation, and T classification, Duke's stage, total protein ,TLC and ALT level were  the predictors of rectal cancer metastasis. ROC curve analysis revealed that AUC of serum UA was 0.82 , with sensitivity of 63.0 and specificity of 95.0. for prediction of metastasis in rectal cancer patients. Conclusion: Serum UA may be a useful marker in assessing tumor metastasis in patients with rectal cancer.