The expression of angiotensin II type 1 receptor (AT(1)R) and angiotensin II type 2 receptor (AT(2)R) in aldosterone-producing adenoma (APA) of the adrenal gland was detected, and their relationship with clinical indexes of APA was analyzed. The mRNA expression of AT(1)R and AT(2)R in 50 cases of APA and tissues adjacent to tumors and 12 cases of normal adrenal tissues was detected by using reverse transcriptase polymerase chain reaction (RT-PCR). The expression of AT(1)R and AT(2)R proteins in paraffin-embedded slices of tissue was detected by immunohistochemistry. The expression of AT(1)R in adenoma, tissues adjacent to tumor, and normal tissues of the adrenal gland showed no significant differences. The expression of AT(2)R in APA tissue was lower than that in normal adrenal gland tissues (P < 0.05). Correlation analysis of the mRNA expression level of AT(2)R and clinical data from patients demonstrated that AT(2)R expression was negatively related to plasma aldosterone concentration (PAC) (r=-0.467, P < 0.05), but positively related with plasma renin activity (PRA) (r=0.604, P < 0.05). It is concluded that down-regulation of the AT(2)R expression is possibly related with the tumorigenesis of APA.