Police in Calderdale are appealing for information following the attack that happened on Sunday March 19 at around 4pm on Delf Hill Road.
The male victim was approached by another man who punched him several times in the face.
He suffered serious injuries to his face and was taken to Bradford Royal Infirmary for urgent medical treatment.
The suspect is described as a white male, around 35-years-old, short blonde hair, 5ft 7 and stocky build.
He was wearing a blue coat and also had a rucksack on his back at the time of the assault.
Anyone with any information about this incident, or witnessed the assault, is asked to contact the police via 101 quoting crime reference 13170126009.