Objective To investigate the expression of PPAR-γ in rectal carcinoma and the relationship between the expression of PPAR-γ and apoptosis in rectal carcinoma. Methods Tissue microarray and immunohistochemistry were used to detect the expression of PPAR-γ gene, bcl-2 and bax in 16 cases of the normal rectal tissue, 16 cases of rectal adenoma and 80 cases of the rectal carcinoma. TUNEL was used to detect of the AI in 80 cases of the rectal carcinoma. Results The positive rate of PPAR-γ expression in normal rectal tissue, rectal adenoma and adenocarcinoma were 6.3%, 25.0% and 71.3% respectively. Clinicopathological analysis showed that the in-crease of PPAR-γ expression were not associated with age, sex and histological classification (P > 0.05), but associated with differentiation grades, pathological stages, lymph nodes metastases and 3-year survival rate (P < 0.05). The expression of PPAR-γwas positively correla-ted with bcl - 2 and bax. AI was negative related with PPAR-γ (r = -0.51, P < 0.05). Conclusions PPAR-γ gene may play a role in the oncogenesis and progression of rectal carcinoma. The abnormal regulation of apoptosis may play an important role in the pathogenesis of rectal carcinoma. Detection of PPAR-γ is of great value for diagnosing colorectal carcinoma, and evaluating malignancy extent and prognosis.