OBJECTIVE: It is known that bilirubin interferes the measurement of uric acid negatively in uricase-peroxidase method. In Korea, endemic area of viral hepatitis, there are so many patients who have high serum bilirubin, that we tried to estimate the effect of bilirubin on measurement of uric acid. METHOD: All the measurements were done by automatic chemical analyzer (Cobas Integra 700, Roche Diagnostics, Basel, Swiss) in quadruplicate. We performed two kinds of experiments. Firstly, we mixed sera of two patients (one who have high uric acid level and the other high bilirubin level) in different volume and measured the level of uric acid and bilirubin in each mixture. Secondly, we made pool of sera with six patients who had high uric acid level, then selected the sera of 23 patients (who have various bilirubin level), and mixed every selected serum with the pooled sera in same volume. In each step we measured the level of bilirubin and uric acid, respectively. We calculated the expected values of uric acid on every mixed specimen, compared them with measured values and obtained recovery rates. RESULTS: The recovery rates of uric acid in various concentrations of bilirubin were from 94 to 101%. There were statistically no correlations (r=-0.16, p>0.05 and r=-0.25, p>0.05, respectively in each experiment) between the bilirubin levels and the recovery rates of uric acid. CONCLUSION: Practically, bilirubin did not significantly interfere the measurement of uric acid.