The mandibular primary growth center (MdPGC) of human fetus was conspicuously defined in the soft X-ray view of fetal mandibles. As the peripheral adaptive growth of mandible advances during the postnatal period, the MdPGC image became overshadowed by condensed cortical bones in soft X-ray view. In this study, we traced a sclerotic sequela of MdPGC during the postnatal period. Panoramic radiograms of 200 adults and soft X-ray views of 30 dried adult mandibles were analyzed by statistical methods. The former clearly showed an MdPGC below the middle portion of apices of canine and first premolar, which was distinguishable from mental foramen, and the latter also showed the MdPGC at the same area as a radiating and condensed radiopaque image, measuring 0.5-1.0 cm in diameter. This MdPGC position was seldom changed in the elderly people, even in the edentulous mandibles. Additionally, in the radiological examination, the benign tumors including odontogenic cysts hardly involved the MdPGC, while the malignant tumors of both primary and metastatic cancer frequently destroyed the MdPGC.