Spontaneous regression of sinus pericranii has not been reported in the literatures. The aurthors presented a very rare case of sinus pericranii, which was diagnosed as early as nine days after birth and completely disappeared in seven years. The patient was a nine-day-old boy from normal delivery in full term, who had a soft tumor simulating cephalhematoma in the right parietal region. The overlying scalp looked like a hemangioma bitemporally connecting with strikingly dilated scalp veins. Soft X-ray examination of the skull revealed a homogenous mass and a small bone defect beneath the mass. Venous blood was punctured from the tumor. By means of direct injection of contrast media into the tumor, the superior sagittal sinus as well as many extracranial varicositous veins were shown. No intracranial vascular anomaly. In a year the tumor spontaneously declined and in the following seven years it disappeared completely. Pathogenesis of this lesion was discussed with special reference to cephalhematoma and a possibility of spontaneous regression of sinus pericranii was stressed.