Purpose: To determine the relationship between pregnancy-associated plasma protein-A (PAPP-A) levels and preeclampsia and HELLP syndrome at last trimester and to investigate if the severity of preeclampsia would be associated with PAPP-A levels. Methods: Four groups were constructed; mild-preeclampsia group consisted of 19 women, severe-preeclampsia group 17, HELLP group 5 and control group 32 women. All groups were matched strictly for gestational age at last trimester. Maternal blood samples for PAPP-A were collected as soon as the patients were diagnosed as preeclampsia or HELLP syndrome at last trimester and compared. Results: Mean ages of participants, parity, gestational week, and fetal weights were similar. Mean PAPP-A levels were significantly higher in preeclampsia and HELLP groups compared to control group. PAPP-A levels were not different among mild-severe preeclampsia and HELLP groups. There was significant, positive and strong correlation between gestational age and PAPP-A level and also between fetal weight and PAPP-A levels (correlation coefficents = 0.83 and 0.78 respectively). Conclusion: PAPP-A level at last trimester increases in all mild-severe preeclampsia and HELLP syndrome, but is not predictive for severity of preeclampsia or HELLP syndrome. [ABSTRACT FROM AUTHOR]