Background and Objective : Trichomonas vaginalis infection is a common sexually transmitted protozoal infection and is associated with several adverse outcomes such as preterm labour, delivery of a low-birth weight infant, and facilitation of sexually transmission of human immunodeficiency virus. In Iran, the prevalence of trichomoniasis has been reported between 2 to 8%. The aim of the study was to investigate the prevalence of this infection among women referred to a laboratory in Zanjan.

  Material and Methods: ­In this Cross-sectional study, 328 women were selected via convenience sampling. Because of vaginal discharge, itching, burning and malodor, they were referred to a laboratory by a gynecologist. After preparing a demographical check list, the vaginal specimens were examined by wet smears for Trichomonas vaginalis, in 2010. To analyze the data, we use chi square and fisher exact test.

  Results: The clients (54.43%) ­are 25-­34 years old, homemaker­(87%), illiterate or­­ primary school education­ (48%).­The prevalence of T.­ Vaginalis infection is­ 6.4%.­ there is no significant relationship between T.­Vaginalis infection and factors like age, education level, marriage age, contraceptive method, occupation, dwelling place and number of labour.

  Conclusion: In comparison with other studies, the prevalence of Trichomonas vaginalis in Zanjan is moderate. Because of co-existing with other sexually transmitted diseases (STDs), we suggest conducting further studies about the prevalence of other STDs in Zanjan.

  Keywords: Trichomonas vaginalis, Prevalence, Zanjan