Oral treatment for trichomonas vaginalis infection is now well established. In a previous paper, we established the value of a high single dose regimen of metronidazole for this condition by demonstrating its efficacy in a double-blind controlled study. Tinidazole is another accepted trichomonacide. By means of a single-blind controlled trial, we demonstrate that a 2 g single dose of tinidazole is as effective as a 2 g single dose metronidazole in the treatment of vaginal trichomoniasis. The cure rate for tinidazole was 95% and for metronidazole it was 97.5%. No side-effects were reported with either regimen.