We developed a novel method for the detection of Mycoplasma hominis from vaginal swabs using an indirect immunofluorescence technique. It is a rapid and simple method that can be finished in only 5hr and is more sensitive than the usual culture isolation method. The indirect immunofluorescence method was applied to vaginal smears from 193 healthy women and 33.7% gave a positive test. This value was much higher than that (11.4%) obtained from the same specimens by the culture method. When vaginal smears were subjected to Papanicolaou staining after the indirect immunofluorescence method, the specific immunofluorescence of the epithelial cells was located exactly at the sites of granular aggregates stained with Papanicolaou stain. A histological examination by Papanicolaou staining showed that the incidence of inflammation seems to be slightly higher in M. hominis-carriers than in non-carriers.