The aim of the study was to assess the depth of myometrial invasion and cervical involvement by endometrial cancer using preoperative 6.5-MHz, high-frequency transvaginal ultrasonography as compared with postoperative assessment using histopathological examination. The study included 47 patients with histologically proven cancers of the endometrium. All patients underwent transvaginal sonography before surgery. The depth of myometrial invasion was classified as none, inner half of the uterine wall, and outer half of the uterine wall. Cervical spread is recorded as positive or negative. Of 36 (76.6%) patients with proven myometrial invasion, 33 cases (91.66%) were revealed by sonography. Histologically proven cervical invasion that correlated with sonography was shown in 3 patients (75%). In 7 patients (14.9%) ultrasonography could not correctly predict the depth of myometrial invasion. The depth of invasion was underestimated in 4 (8.5%) cases and overestimated in 3 (6.4%) cases. Preoperative assessment of invasion of the uterine wall and cervical spread by transvaginal ultrasonography had an accuracy of 85 and 97.8% if correlated with the definitive histopathological examination. The role of transvaginal ultrasonography in preoperative assessment of the depth of myometrial invasion and cervical involvement in patients with endometrial cancer needs to be studied further before making reliable conclusions.