An apparatus and method is configured to detect the proximity of an object using a proximity sensor in a portable terminal. A method for detecting the proximity of an object in a portable terminal mounted with a proximity sensor includes setting a reference light-receiving quantity according to a hairstyle of a user of the portable terminal, emitting light, detecting a light-receiving quantity corresponding to the emitted light, and determining the proximity/non-proximity of an object by comparing the light-receiving quantity with the reference light-receiving quantity.