Abstract: The grain boundaries in high purity Fe-0.2%P-2%Cr-C alloys were analyzed by high resolution Auger electron spectroscopy. The results show that a large number of carbides in 0.3 μm average diameter exist at intergranular fracture surface. PHRs (Peak Height Ratio) of carbon at the boundary regions with carbides are 34.9% and 33.3% for two alloys, respectively, and the PHRs of chromium are 14.6% and 7.3%. The carbides are identified as chromium rich carbides. Remarkable segregation of phosphorus and carbon takes place at grain boundary regions without carbides. The segregation levels (PHR) of phosphorus at the boundary regions without carbides are 20.2% and 19.6% for two alloys, respectively, and its enrichment factors are 56 and 54. The PHR values of carbon at the regions are 8.6% and 12.6% for two alloys, respectively, and its enrichment factors are 308 and 450. With increase in carbon content in the alloy, carbon segregation is increased, while phosphorus segregation is slightly decreased.