In order to assess the toxicological potential and thus forecast the potential effect posed by untreated hospital wastewater discharges according to exposed ecosystem, the ecotoxicological analysis were performed. During the study the real samples of hospital wastewater were used. The ecotoxicological analysis included the following tests: immobilization test according to crustacean Daphnia magna; mortality test according to crustacean Thamnocephalus platyourus and Artemia salina and growth inhibition test relative to ciliates Tetrahymena termophila. Within each test, the value of ecotoxicological indicators EC50 (effect concentration) were estimated. The EC50 value were transformed into the Toxic Unit (TU), basis of which the analyzed hospital wastewater samples were classified. The results proves that hospital wastewater pose a serious threat to exposed aquatic organisms and their insufficient purification as well as uncontrolled discharge into the environment may cause adverse changes in the environment.