To obtain a valve seat for internal combustion engine, excellent in wear resistance and machinability, at a low cost while obviating the necessity of the use of an expensive, hard, high alloy material and the addition of hard grains, by forming the valve seat by the use of a high-Mn Fe-base alloy material and causing work hardening during operation.

A valve seat 1 for internal combustion engine is formed by using a high-Mn Fe-base alloy material. It is preferable that this high-Mn Fe- base alloy material has a composition consisting of, by weight, 0.9-1.2% C, 10-15% Mn, 0.3-0.8% Si, and the balance Fe with inevitable impurities. This valve seat 1 can be formed by mixing powdered raw-materials of the above composition by the ordinary powder metallurgy method, compacting the resultant powder mixture, sintering the resultant green compact, applying hot-forging to the resultant sintered compact, and further applying, if necessary, heat treatment, finish working, and infiltration or impregnation treatment. This valve seat 1 has about Hv 200 Vickers hardness and is easy of machining, and further, it can be work-hardened to about Hv 400 by the impact load of an engine valve 2 seated on a seat part 1a during operation.