A sacrococcygeal teratoma (SCT) may be completely concealed within the pelvis and therefore not be visible externally. Symptoms of such an SCT can be very aspecific. We present 4 patients with an intrapelvic SCT. The first patient, a newborn girl, had an antenatally-diagnosed cystic mass in her pelvis, which was a benign SCT. After removal she suffered from neurogenic bladder dysfunction. The second patient was a 2-year-old boy who after two incomplete resections of a benign intrapelvic SCT, developed a malignant SCT. The other 2 patients, 2 girls aged 4 and 15 years, both presented with constipation and abdominal pain and were diagnosed as having an SCT. Early detection and radical excision, including removal of the os coccygis, are necessary to prevent development of malignancy. Long-term functional sequelae can occur after excision.