Description: Major morphometric measurements (Length of body (L), Tibia (T), Femur (F).) in Pelophylax ridibundus from populations inhabiting two bodies of water in the outskirts of Plovdiv: one relatively clean and the other - polluted with pesticides, were analyzed. In both populations, independent of the characteristics of the living environment, there is clear sexual dimorphism - females are superior to males in size. When living in conditions of pesticide contamination, statistically reliable reduction of body size in both sexes of P. ridibundus is found