A process for the production of an optically active (R)-(-)-3-halo-1,2-propanediol which comprises contacting a 1,3-dihalo-2-propanol with a dehalogenase originating from a microorganism belonging to the genus Corynebacterium or Microbacterium. This process makes it possible to produce the (R)-(-)-3-halo-1,2-propanediol, which is highly useful as a starting material in the synthesis of various drugs and physiologically active substances, theoretically at a yield of 100%.