Trichomonas vaginalis is a vaginal protozoon causing the most prevalent nonviral sexually transmitted disease. Culture is considered as the most reliable and gold standard among conventional diagnostic methods in the detection of T. vaginalis. In the present study, the diagnostic effect of subsequent blind culturing of vaginal secretion samples in Diamond's complete medium at every 48 h was investigated in 93 women. Vaginal secretion samples were examined by wet mount and inoculated into Diamond's complete medium. All tubes were subcultured to a new culture tube blindly 5 times at 48-h interval and checked microscopically everyday for the presence of T. vaginalis trophozoites. Three of 93 women were found to be positive both by wet mount and standard culture methods. Five more positive results were detected with subsequent blind culturing among 90 negative results. This system appears to be a useful method for the detection of T. vaginalis.