Grain-size evolution with increasing annealing time has been investigated in polycrystalline Co2FeSi films. The samples were prepared by sputtering giving differing grain sizes. Large grains were formed after annealing at 500 degrees C, with grains over 200 nm forming in the L2(1) phase in a layer-by-layer mode. Further annealing causes a decrease in the average grain size, agreeing well with previously reported results for Co2MnSi. Magnetic measurements showed moments with values of up to 75% of those predicted from the Slater-Pauling curve providing further evidence for the formation of the L2(1) phase.