Iron diffusion in an Fe‐3% Si alloy has been studied by means of the Mo¨ssbauer effect. The results in this iron‐base system agree closely with conventional measurements and do not appear to exhibit the factor of 2 anomaly with the Singwi and Sjo¨lander analysis which Knauer and Mullen observed for iron in dilute solution. The values obtained can be described by the equationD=0.20(−0.15;+0.65) exp[−49 600±3700/RT].