EPH-gestosis, especially its serious clinical complications, poses a high threat for the mother and fetus. The aetiology of this condition has not yet been completely explained. During gestosis the kidneys are most frequently involved, although other organs show changes also. The consequence of renal changes is reduction of renal blood flow and glomerular filtration rate. The studied group comprised 96 women with gestosis with at least two signs treated at the Department of Pathological Pregnancy, WAM in the years 1986-1988. The control group included 52 healthy pregnant women. Serum levels were determined of urea, creatinine-uric acid and protein. The obtained results were subjected to statistical analysis by Student's t test, accepting p less than 0.05 as statistically significant. In the group with EPH-gestosis, as compared to the control group, the uric acid level was significantly raised, while that of protein in the serum was slightly decreased. The levels of creatinine and urea were not significantly different between these groups. The raised serum uric acid level in gestosis cases was correlated with a higher frequency of instrumental labours and worse condition of the newborns at birth.