Police say a man and woman asked the driver to take them from Manhattan to East 174th Street and Prospect Avenue.
At one point during the ride, the woman allegedly held a knife to the cab driver's throat and demanded money.
Police say that the two grabbed an undetermined amount of cash from between the passenger and driver seat before fleeing.
The driver suffered minor injuries while trying to fight them off.
The woman is described as in her mid-30s, approximately 5 feet, 8 inches tall and weighing 160 pounds.
The man is said to also be in his 30s and is said to be approximately 5 feet, 8 inches tall, weighing 180 pounds.
Anyone with information on the case should contact the Crime Stoppers hotline at 1-800-577-TIPS, or text CRIMES and then enter TIP577, or visit www.nypdcrimestoppers.com.