Background: The measurement of 24-hour uric acid excretion is important to evaluate the disease status as well as to select the kind of uric acid lowering agents in gouty patients. However, 24-hour urine collection is inconvenient, and frequently unreliable due to errors in collection. We investigated the utility of the random urine uric acid to creatinine ratio for predicting 24-hour urine uric acid excretion in gouty patients. Methods: The cross-sectional study included 37 gouty patients without any use of uric acid lowering agents. Random urine uric acid and creatinine specimens were obtained, and 24-hour urine collections were conducted to the evaluate uric acid excretion and renal function. Chronic kidney disease was defi ned as the creatinine clearance (CCr) levels below 60 ml/min/1.73 m2. Results: The mean of 24-hour uric acid excretion was 602.4±236.0 mg, and thoseof serum uric acid levels and CCr values were 7.31±1.31 mg/dl and 100.9±33.2 ml/ min/1.73 m2, respectively. Random urine uric acid to creatinine ratio was closely correlated with the absolute and log transformed 24-hour urine uric acid excretions (γ =0.450, p=0.005; γ=0.474, p=0.003, respectively). In the linear regression analysis, the amount of absolute 24-hour urine uric acid excretion was estimated by 0.812x (random urine uric acid to creatinine ratio) + 290.466 (R2=0.450, p=0.005). The correlation between random urine uric acid to creatinine ratio and 24-hour urine uric acid excretion was also found in the patients with chronic kidney disease (γ=0.900, p=0.037). Conclusions: Random urine uric acid to creatinine ratio showed positive correlation with the absolute and log transformed 24-hour urine uric acid excretions. The random urine uric acid to creatinine ratio would be a good predictor of 24-hour urine uric acid excretion in gouty patients.