A method and apparatus for authenticating a user using a vein pattern are provided that project a near infrared (NIR) ray toward a skin of the user using a light emitting diode (LED), where the user is adjacent to a terminal including the LED. An image sensor receives a light reflected by the skin, generates a vein pattern of the skin based on an image generated using the received light, and authenticates the user as a registered user of a pre-stored vein pattern when the generated vein pattern matches the pre-stored vein pattern.