This study was designed to investigate the in vitro inhibitory activity of aqueous extract of propolis (AEP) on the growth of Trichomonas gallinae in comparison to metronidazole. Aqueous extract of propolis inhibited the growth of T. gallinae trophozoites and the level of inhibition varied according to the extract concentration and incubation times. The highest reduction of parasitic growth (100%) was observed in cultures treated with 100 and 75 mg/ ml of propolis aqueous extract after 24 h. The same result was detected in cultures treated with 50 mg/ ml of AEP but after 48h. While Growth reduction by 92.5 and 80% was observed in 25 and 12.5 mg/ml propolis-treated cultures respectively after 96 h. Minimal lethal concentration of aqueous extract of propolis was 50mg /ml after 48 hours.In comparison complete inhibition of parasite growth was obtained by metronidazole (50 µg/ml) after 24hours. Light microscope observations revealed changes of the pear-shaped aspect of the cell as a result of presence of large vacuolations in the cytoplasm of the trophozoites. Our results hold the perspective for the utilization of propolis as an antitrichomonal agent after the complementary in vivo studies.