The present study investigated serum and placental tissue prolidase enzyme activities in the preeclampsia. Serum and placental tissue samples from 24 women with preeclampsia and 25 women with healthy pregnancy were collected. Prolidase enzyme activity was determined using a photometric method. Data such as maternal age, systolic and diastolic blood pressure, gestational age and fetal birth weight were assesed. Serum prolidase activities were found significantly lower and placenta prolidase activities were significantly higher in preeclamptic pregnancy than those in controls. Statistically significant correlations were found between placenta prolidase levels and gestational age, fetal birth weight. In conclusion, we conclude that collagen turnover rate is increased in preeclamptic placenta. However, further studies are needed how prolidase affect gestational age and fetal birth weight in preeclampsia.