A system for transferring a substrate may adjust a suction force to a suitable level. The system may include a work table, a picker, and a pressure measuring unit. The work table may include a work area for supporting the substrate. The picker may be disposed above the work table and may include a suction unit for providing the suction force. The pressure measuring unit may overlap the suction unit and may include a pressure-sensitive element for facilitating adjustment of the suction force.