Lesions occurred in the female genital tract of 10 of 16 (63%) koalas, Phascolarctos cinereus, examined in Victoria. Inflammation of the uterine horns was seen in all 10 affected koalas; six of these had vaginitis and eight also had salpingitis. Cystic dilation of the ovarian bursa, occasionally with hydrosalpinx, was seen in six koalas with concurrent inflammatory lesions of the lower tract. Cystic lesions were considered to have developed as chronic sequelae to previous inflammation in the ovarian bursa. Lesions were not found in the ovaries. Lesions in the urinary tract lesions were noted in four koalas with genital tract pathology. The significance of these findings in relation to the reproductive success of the koala population on Phillip Island is discussed.