The present study was aimed to evaluate the efficacy of anthelmintic agents against intestinal nematodes found in European bison. It was performed between October 2016 and May 2017, using Egg Hatch Assay (EHA) and Larval Development Assay (LDA). The parasites were obtained from faecal samples, harvested from bisons in Romania and Sweden. The efficacy of albendazole (ABZ), mebendazole (MBZ) thiabendazole (TBZ) and pyrantel (PYR) was tested. In EHA, the maximum efficacy was observed in MBZ (EC 50 = -0.227 µg/ml), and then TBZ (EC 50 = -0.2228). ABZ had a weaker result, EC 50 being 0.326 µg/ml. All tested benzimidazoles registered hatching percentages below 50%, reflecting the lack of parasitic resistance. MIC obtained in the LDA tests were 0.2144 µg/ ml for TBZ, 0.2792 µg/ml for PYR, 0.5429 µg/ml for MBZ, while ABZ came last (MIC = 0.8187 µg/ml). The in vitro tests proved the antiparasitic molecules efficacy against bisons nematode population and a limited risk of inducing resistance phenomena.