Atom probe analysis results of Co-22at%CR bulk alloy and its thin films are presented. While no compositional inhomogeneity is detected from the bulk sample, a significant compositional fluctuation is present in the thin film specimen which is sputter deposited on a heated substrate. The concentration of the Cr enriched region is in the range of 30 - 40 at.%Cr, while that of the Cr depleted region is approximately 5 at.%Cr. Such compositional fluctuations are present within a grain. These results are in agreement with NMR and TEM results.