The incidence of monilial vulvovaginitis was compared between 3179 women given oral contraceptive drugs and 5240 not given them. Clinical monQiasis in the treated patients progressively increased as the duration of oral contraceptive medication increased, whereas the controls' rate of infection was fairly constant. Of the 3179 women given oral contraceptive medications, 44 had had clinical vulvovaginal moniliasis before and continued to have the problem while taking the medications; 181 experienced it for the first time. More than 1 in 10 of the husbands of the 225 affected women had balanoposthitis. One in 17 of the 225 had a hereditary background of diabetes mellitus, but their oral glucose tolerance tests were normal. The incidence of candidiasis was not related to the type of oral contraceptive used. A small percentage of women suffered genital moniliasis repeatedly; such infections did not tend to clear up until the oral contraceptive medication was discontinued.