Vaginal swab specimens were collected from 310 female patients attending two medical centers in Baghdad.T_._ vaqinalis was isolated -from 30 patients with a prevalence rate o-f (9.77%). Different age groups were studied , a high in-fection rate (10. 77.) was recorded in patients at child - bearing age (20 - 4O) years. Among the examined patients, the illiterate ones had the highest rate of infection (15.6%). Clinically , (23.3%) o-f the patients were acutely infected and (76.7%) were chronically infected. Of the latter group , a higher in-fection rate ( 65.2%7. ) was -found in those taken incomplete treatment compared to the patients taken a complete one (34.8%). The two modifications described in this study were found to be superior to the original Diamond's medium for the growth of 5 T_._ vaginalis isolates. A comparison between wet mount, culture, LAT, and 1IFA for the diagnosis of trichomoniasis in 110 patients was undertaken. Highly significant differences were found between the immunological tests (LAT and UFA), and the other two parasi tological tests. The IIFA was found to be more sensitive (93.3%) than LAT (73.3%). While, the specificities of IIFA and LAT were (74.%7) and (80%) respectively . Sixteen isolates of T. vaginal is were compared among themselves on the basis of their isoenzyme patterns of five enzymes (MDH, ME, GPI, PGM, and G6PD) by polyacrylamide gel electrophoresis. From the isoenzyme patterns obtained,these isolates were divided into 8 groups(zymodemes). (A correlation between the biochemical data and the severity of trichomonal infection reveals that -four different zymodemes fell in each the severe type of infection and the mild - moderate one. This indicates the presence of an intraspecific variation among these isolates, and possibly there is more than one strain of T. vaginalis in Iraq.