The present study was undertaken to examine the reliability of the sonographic diagnosis in 705 gynecological patients. The determination of the lesions was defined according to the operative diagnosis. The sensitivity, specificity and positive predictive value of the ultrasound technique were evaluated using the surgical findings as ''gold standard''. In 631 patients (89.5%) the ultrasound examination established a correct diagnosis. The sensitivity and specificity of the ultrasound examination varied between 75-95.3% and 93.3-100%, respectively. The positive predictive value was found between 89.7 and 100%, while the false sonographic results were 10.4%, which included those of ectopic pregnancies. It is thus concluded that ultrasonography as compared to the surgical findings has proved to be of great value in establishing a gynecological diagnosis.