Abnormal proliferation is an important pathological feature of autosomal dominant polycystic kidney disease (ADPKD). Many drugs inhibiting cell proliferation have been proved to be effective in slowing the disease progression in ADPKD. Recent evidence has suggested that peroxisome proliferator-activated receptor gamma (PPARgamma) ligands have anti-neoplasm effects through inhibiting cell growth and inducing cell apoptosis in various cancer cells. In the present study, we examined the expression of PPARgamma in human ADPKD kidney tissues and cyst-lining epithelial cell line, and found that the expression of PPARgamma was greater in ADPKD kidney tissues and cyst-lining epithelial cell line than in normal kidney tissues and human kidney cortex (HKC) cell line. Rosiglitazone inhibited significantly proliferation of cyst-lining epithelial cells in a concentration- and time-dependent manner. These effects were diminished by GW9662, a specific PPARgamma antagonist. Cell cycle analysis showed a G0/G1 arrest in human ADPKD cyst-lining epithelial cells with rosiglitazone treatment. Analysis of cell cycle regulatory proteins revealed that rosiglitazone decreased the protein levels of proliferating cell nuclear antigen, pRb, cyclin D1, cyclin D2 and Cdk4 but increased the levels of p21 and p27 in a dose-dependent manner. Rosiglitazone also induced apoptosis in cyst-lining epithelial cells, which was correlated with increased bax expression and decreased bcl-2 expression. These results suggest PPARgamma agonist might serve as a promising drug for the treatment of ADPKD.