Majority of the cardiovascular diseases have many predisposing and aggravating factors that cause atherosclerotic vascular injuries. Uric acid has been reported as a contributory factor that negatively interfere with the pathology of cardiovascular diseases and may even induce cerebrovascular complications. Allopurinol is the commonly used uricosuric agent in patients with gouty superimposed by urate renal stone. The present study aimed to identify the effect of allopurinol on the serum lipid parameters as an inevitable complication in patients diagnosed with renal stone. Fifteen patients diagnosed with urate renal stones were treated by allopurinol (300 mg/day for 6 months) and blood samples were obtained for laboratory assessment of the lipid profile. The outcome showed significant alterations of lipid parameters (with elevated total cholesterol (TC) and triglycerides (TG), plus reduced HDL serum levels); hence LDL, VLDL, and non-HDL were elevated accordingly. The study led to the conclusion that using allopurinol in subjects with apparently normal lipid parameters was associated with elevation of the predisposing factors of cardiovascular diseases. These findings give a general clue and might be helpful in selection of appropriate uricosuric agents for treatment of patients with cardiovascular diseases, suggesting that, the avoidance of allopurinol is advisable in predisposing high risk groups of patients, and necessitating the searching for safe-alternative hypouricemic agents in such group.