The purpose of this study was to determine the isolation rates of Mycoplasma 
hominis and Ureaplasma urealyticum from three populations of women and also to 
relate the presence of these microorganisms with some indicators of nonspecific 
vaginitis. Three hundred vaginal swabs were taken from delivery, pregnant and 
control (not pregnant) women. Cultures were done in E broth supplemented with 
arginine or urea. M. hominis was isolated in 5% at delivery, 12% from pregnant 
and 5% from control women and U. urealyticum was isolated in 21%, 31% and 28% 
respectively. There was statistical difference in the isolation rate of M. 
hominis in pregnant women respect to the other groups. Both microorganisms were 
more frequently isolated in women with acid vaginal pH, amine-like odor in KOH 
test, clue cells and leucorrhea. M. hominis was isolated in 17% and U. 
urealyticum in 52% from women with nonspecific vaginitis. M. hominis was 
isolated in 2% and U. urealyticum in 13% from women without nonspecific 
vaginitis. Although the presence of clue cells and amine-like odor in KOH test 
have relationship with Gardnerella vaginalis, these tests could also suggest the 
presence of these mycoplasmas.