The behavior of oxygen precipitation was investigated in radial direction using Si wafers with different generation area of vacancy-related defects. Oxygen precipitation is more enhanced in vacancy-rich region than in interstitial-rich region. The behavior of oxygen precipitation in the radial direction is strongly dependent on the size of vacancy-rich region which is related to crystal growth condition. Anomalous oxygen precipitation occurred in the marginal vacancy-rich region and the inner edge of interstitial rich region. In the marginal interstitial-rich region, however, oxygen precipitation is suppressed to nearly zero.