BACKGROUND: Based on our knowledge, there have been no ultrasonographic studies on uterine involution following induction of abortion in the bitch. OBJECTIVES: To evaluate ultrasonographic features of uterine involution following induction of abortion. METHODS: In a concurrent study, pregnancy was terminated in 6 bitches in the third trimester of pregnancy by ultrasound guided induced fetal death. Ultrasonographic examination of the reproductive tract carried out after the day of complete abortion up to complete uterine involution, in which uterine dimensions were unchanged within two consecutive evaluations. Uterine shape, size, and echogenicity as well as wall layering were evaluated in ultrasonographic evaluations, and mean values were measured in both placental and interplacental regions. RESULTS: Ultrasonographic features revealed that, uterine wall is detected on ultrasound images having six different layers on the basis of its echogenicity. Wall layering was very explicit and distinct within the first week after abortion and lost its distinction in the course of uterine involution. On the day after abortion, placental regions measured approximately twice the size of the uterus in interplacental areas. In the first week, the mean values of the placental and interplacental thickness were 2.11±0.31cm and 1.12±0.20 cm respectively, measured in uterine horns. After the third week, the placental and interplacental regions lost their distinction and thickness. In the last two weeks, uterine horns were almost equal in dimension in every part. The time of complete involution varied amongst these 6 different bitches, being in the 6th, 8th, 9th, 10th, and 13th week after the induction of abortion. CONCLUSIONS: The findings of this study could be a basis for ultrasonographic evaluation of abnormal uterine structures and also detection of uterine involution time after abortion or parturition.