Objective: To diagnose renal cell carcinoma at early stages and for better prognosis, the main objective of our current study was to understand any association with diabetes with relation to age, gender, history of disease, diabetic laboratory parameters, tumor size and grade. Materials and Methods: This hospital based study was carried out using data retrieved from the register maintained in the Department of Biochemistry of Nepalese Army Institute of Health Sciences between $1^{st}$ December, 2011 and $31^{st}$ May, 2012. The variables collected were age, gender, HbA1c, serum creatinine, fasting blood glucose. One way ANOVA was applied to examine statistical significance of differences between groups. The LSD post hoc test was used for the comparison of means of case groups. Results: Of the total 140 cases of renal cell carcinoma, 79 patients were also suffering from diabetes mellitus. The number of females (47) was more in diabetic RCC patients when compared to males (32). Significance was observed in levels of serum creatinine for tumor size >10cm ($0.0001^*$). The highest value of glycated hemoglobin (8.9%) and fasting blood sugar(148.3mg/dl)in cases of renal cell carcinoma along with diabetes mellitus was found in tumour size of 1-5cm. Conclusion: Diabetes mellitus has independent prognostic significance in RCC in relation to tumour size and grade.