We used ultrasonotomograms to evaluate measurements of the length of the uterus in 38 Japanese women who had had a normal labor and no complicatlons. Decrease in the length of the uterus, although evident with both measurements was more dominant in the case of external measurements. Differences in all measurements between prim- and multiparas were nil. Ultrasonotomograms should find a wide application in studies related to the puerperium.