The magnetic susceptibility of gamma -iron containing 0. 002 to 0. 08 wt% oxygen was investigated in the temperature range 1220 to 1660 K. A considerable influence electronic structure is found. Abnormal behavior of the magnetic susceptibility was discovered in the region 1380 to 1430 K. The anomaly is a property of pure iron and can be explained by the appearance of clusters with magnetic ordering because of spin polarization.