Disclosed is an apparatus and method for detecting slip of a robot. The robot periodically repeats a pattern movement in the order of a uniform motion, a decelerating motion, and an accelerating motion, or in the order of a uniform motion, an accelerating motion, and a deceleration motion. The occurrence of slip of the robot performing a pattern movement is determined by comparing a first acceleration of the robot measured by an acceleration sensor and a second acceleration of the robot measured by an encoder.