A retractable sliding door (10) with automatic alignment to the wall (12) during the closing phase, suitable to alternately open and close a through space (14) made along said wall, comprising a lower guide (18) fixed to the floor and an upper guide (20) forming a support beam. In the upper guide (20) paired prominences (50, 52) and (60) are made constituting the sliding tracks of two or more pairs of wheels (54) and single wheels (58) borne by a shaft (56) and combined with a frame (62) to form a carriage. The lower guide (18) interacts with a roller (24) suitable to fit into a shaped channel with a mixed-line extension (26) made along the lower head of the door (10); the upper guide (20) is provided with a shaped channel (78) having the same and parallel mixed-line configuration as said shaped channel (26). The upper head of the door (10) being provided with means for its suspension to the frame (62) constituting the carriage.