OBJECTIVES To evaluate the prevalence of toxoplasma and cytomegalovirus (CMV) infections in cases of ultrasound anomalies detected in the second trimester of pregnancy. METHODS Serological examinations for toxoplasma and CMV infection were carried out in 655 cases with sonographic findings suggestive of fetal infection, 612 cases with single ultrasound markers and 43 cases with two or more markers. RESULTS In cases of single ultrasound markers, serological examination diagnosed recent toxoplasma infection in 107/612 cases (17.5%) and recent CMV infection in 75 cases (12.3%). Recent toxoplasma infection accounted for 13.8% (52/377) of the intracranial sonographic findings and 23.9% (45/188) of the abdominal findings, whereas recent CMV infections accounted for 12.2 (46/377) and 11.7% (22/188), respectively. Recent CMV infection with sonographic manifestations had higher rates of intracranial than intra-abdominal sonographic findings (46/75 or 61% vs 22/75 or 29%), whereas recent toxoplasma infection with sonographic manifestations had similar rates of intracranial (52/107 or 49%) and intra-abdominal (45/107 or 42%) findings. In cases of two or more ultrasound markers, serological examination diagnosed recent toxoplasma infection in 12/43 cases (27.9%) and recent CMV infection in 10/43 cases (23.3%). CONCLUSIONS Ultrasound findings suspicious for toxoplasma and CMV infection are not pathognomonic for either pathologic entity.