Vissa Esan, owner of Aussie Unity Real Estate in Pendle Hills, was believed to be putting out the garbage in an alley next to his office early yesterday morning when he was attacked.
According to a police statement, they arrived to find Mr Esan suffering from a chest wound.
He was treated at the scene by NSW Ambulance paramedics before being taken to Westmead Hospital, where he died.
Police patrolling Pendle Hill after the stabbing arrested a 30 year-old man nearby, who was taken to Merrylands police station and questioned by both detectives and officers from the homicide squad.
Initial reports claim the attack was random and the men were strangers. Acting superintendent Ian Casha said police still had not determined a motive at this stage.