Primary biliary cirrhosis (PBC) is a progressive cholestatic liver disease frequently leading to development of cirrhosis and its complications. Ursodeoxycholic acid (UDCA) is a beneficial medical therapy for patients with PBC. Improvement in some histological features, but not in histological stage, has been reported after 2 years of UDCA therapy. Thus, longer follow‐up may be necessary to determine whether UDCA has a favorable effect on histological stage of disease and progression to cirrhosis. Our aim was to determine the long‐term effects of UDCA therapy on histological stage and progression to cirrhosis in patients with PBC. Sixteen unselected patients with noncirrhotic PBC who had been on long‐term UDCA therapy (13‐15 mg/kg/d) for 6.6 ± 0.4 years (range, 5‐9 years) were identified and their histological finding during treatment compared with that of 51 noncirrhotic patients with PBC who had received ineffective therapy (d‐penicillamine [DPCA] or placebo) for 5.6 ± 0.07 years (range, 5‐8 years). Histological stage was determined using the Ludwig classification. The rate of progression to cirrhosis (stage 4) was significantly less in the UDCA group than in the control group (13% vs. 49%P= .009). Although the overall rate of progression of histological stage was less in the UDCA group than in the control group (50% vs. 71%), this difference was not significant (P= .1). A marked improvement in liver biochemistries and Mayo risk score was noted in all patients during UDCA therapy; however, this improvement was not significantly different between patients who progressed and those who did not. In conclusion, long‐term UDCA therapy appeared to delay the development of cirrhosis in PBC.