Background. Timely prediction, diagnosis and prevention of complications during the gestational period leading to perinatal loss and maternal mortality are the main tasks of contemporary obstetrics. About 50,000 women die from preeclampsia and eclampsia every year and perinatal mortality ranges from 15 to 25%. Objective. The aim of the research was to study and analyze the microecology of vagina and mammary glands skin in the pregnant women with underlying preeclampsia. Methods. The pregnancy examination was conducted at the Ternopil Regional Clinical Perinatal Center “Mother and Child”. The research involved 25 pregnant women with preeclampsia (the main group) and 15 healthy women with a physiological course of pregnancy (the control group). Material from the pregnant women was taken out of the skin of mammary glands and mucous membrane of vagina, then it was plated out in the nutrient medium for the cultivation and the microorganisms were defined. Results. The quantitative composition of a normal microflora of vagina and mammary glands skin in the control group was within the normal range. The quantitative composition of a normal microflora of vagina and mammary glands skin in the pregnant women of the main group decreased, the representatives of opportunistic and pathogenic flora were found. Conclusions. In the pregnant women with preeclampsia, abnormal microbiocenosis of vagina and breast skin was revealed, the degree of abnormality correlated with the severity of the disease. Our results may provide useful clinical knowledge to a broader understanding of microbiota role in pregnancy complications.