The objective of this retrospective study was to evaluate the usefulness of abdominal and vaginal sonohysterography (SHG; considered both singly and in combination) for the diagnosis of uterine polyps. Fifty fertile women hospitalized for hysterectomy for benign gynecologic indications were enrolled. Main outcome measures were preoperative conventional vaginosonography, transabdominal and vaginal SHG, hysteroscopy and histologic evaluation of the surgical specimen. Conventional vaginosonography had a sensitivity of 33.3% and a specificity of 100%; the predictive values of abnormal and normal scans were 100 and 79.5%, respectively. Transabdominal SHG had a sensitivity of 75% and a specificity of 100%. The predictive value of an abnormal scan was 100%; that of a normal scan 91.2%. Vaginal SHG had a sensitivity of 58.3% and a specificity of 100%; the predictive value of an abnormal scan was 100%, that of a normal scan 86.1 %. The combination of the two kinds of SHG had a sensitivity of 91.7% and specificity of 100%; the predictive value of an abnormal test was 100% and that of a normal test 96.9%. The sensitivity, specificity and predictive values of abnormal and normal hysteroscopic examination were all 100%. In conclusion, the presence of endouterine polyps can be effectively investigated by SHG; nevertheless, hysteroscopy is more sensitive, being capable of detecting even very small endouterine neoformations.