We studied whether the frequency of daily dosing of ursodeoxycholic acid (UDCA) affects its efficacy in patients with chronic hepatitis C. Twenty-nine patients with chronic hepatitis C having received UDCA (600mg) three times a day were randomized to 3 groups with different frequency of the UDCA dosing for another 8 weeks: once a day (qd, n=6), twice a day (bid, n=11), and three times a day (tid, n=10). No significant side effects were noted in all groups, although the compliance was not well in the qd group. Serum ALT levels did not change between 0 and 8 weeks in all groups, suggesting that the efficacy of UDCA was not affected by the divided dosing. Serum levels of total bile acid and UDCA fraction were not significantly changed, either. Thus we conclude that UDCA given bid would be preferable in terms of efficacy as well as compliance.