PURPOSE: To obtain 2-chloropropionic acid in high concentration and selectivity by oxidizing 2-chloropropionaldehyde with oxygen or an oxygen-containing gas in liquid phase in the presence of an iron compound, a chromium compound and a molybdenum compound.

CONSTITUTION: The objective 2-chloropropionic acid can be produced by oxidizing 2-chloropropionaldehyde with oxygen or an oxygen-containing gas in liquid phase (especially at 40-90°C) using a catalyst comprising an iron compound (e.g. ferric salt of 2-chloropropionic acid), a chromium compound [e.g. chromium(II) acetate] and a molybdenum compound (e.g. molybdenum naphthenate). The process enables the industrial production of 2-chloropropionic acid in a low- corrosion environment in high selectivity. 2-Chloropropionic acid having increased concentration can be produced by the process. The process is extremely advantageous because the obtained 2-chloropropionic acid does not contain detectable amount of 2,2-dichloro-propionic acid.