In this study, we make an attempt to assess how the food composition of the Marsh Frog (Pelophylax ridibundus) populations from anthropogenically polluted areas, is affected and what changes in the diet, can be affiliated with environmental pollution. We examined the trophic spectrum of individuals from three populations – two polluted areas (Site 1 - the Chaya River near the confluence with the Maritza River, where the river receives industrial wastewaters and Site 2 – Tsalapitsa Rice Fields near Plovdiv City) and one reference site (control) at Vacha River, south of the town of Krichim (located in a protected zone that is far from industrial or agricultural human activity). The stomach contents were collected by using the stomach flushing method, the stomach contents of 60 (30 males, 30 females) adult individuals were studied. The diet of the population of the Marsh Frog (Pelophylax ridibundus) from the control area – Krichim Town can be characterized with more numerous prey categories and prey taxa, while the trophic spectrum from the other two polluted areas (KCM – wastewaters from heavy metals production and Tsalapitsa Rice Fields – fertilizers and pesticides use) consists of significantly less numerous prey taxa. The trophic niche breadth is also larger at the reference site (12.10) and has lower values at the two polluted sites.