In this study, the serum levels of the pregnancy zone protein (PZP) were determined by PZP-single radial immunodiffusion in 708 cases of normal pregnancy, 207 with abormal pregnancy and 188 with gynecological tumors. The results indicated that serum PZP levels in the normal pregnancy was detectable 5 weeks after gestation. It increased with the advance of gestational weeks, and reached a peak level in week 40. The serum PZP levels in 81.7% of patients with threatened abortion but not aborted were within the normal range, and also mostly in those with pregnancy-nduced hypertension, intrauterine growth retardation (IUGR), anencepbalus and ectopic pregnancy; the serum PZP levels in 51.6% of patients with invasive moles and 80.0% with choriocarcinoma, respectively, were lower than in normal controls. In gynaecological tumors, the serum PZP levels were significantly higher in patients with ovarian carcinomas than in those with other ovarian tumors (P<0.01), and in those with endometrial or cervical carcinoma In this study, the serum levels of the pregnancy zone protein (PZP) were determined by PZP-single radial immunodiffusion in 708 cases of normal pregnancy, 207 with abormal pregnancy and 188 with gynecological tumors. The results indicates that serum PZP levels in the normal It was increased with the advance of gestational weeks, and reached a peak level in week 40. The serum PZP levels in 81.7% of patients with threatened abortion but not aborted were within the normal range, and also mostly in those with pregnancy-nduced hypertension, intrauterine growth retardation (IUGR), anencepbalus and ectopic pregnancy; the serum PZP levels in 51.6% of patients with invasive moles and 80.0% with choriocarcinoma, respectively, were lower than in normal controls. , the serum PZP levels were significantly higher in patients with ovarian carcinomas than in with other ovarian tumors (P <0.01), and in those with endometrial or cervical carcinoma