21 infants and children with ovarian teratomas are reported. Calcification or ossification occurred in 68%, a higher figure than quoted in prior series. Teeth were recognized in 29% of these. A lucent fat-containing mass was appreciated in only two patients. In younger children the tumor was more frequently abdominal rather than pelvic. In two patients the tumor was malignant. A patient with an amputated freely mobile teratoma is reported in detail and the differential diagnosis of mobile abdominal calcifications discussed.