Abstract: A method for mounting a flap (3) on a workpiece (1) in a precisely positioned fashion, in particular for mounting a vehicle door on a vehicle body. A robot guided gripping tool (5) has a securing device (14) for holding the flap (3) and a sensor system (18) permanently connected to the gripping tool (5). In a first step, the gripping tool (5) is moved, within the scope of a positioning phase (A-2), from a proximity position (37), which is independent of the position of the workpiece (1) in the working space (27) of the robot (7), into a mounting position (29) in which the flap (3) which is held in the securing device (14) is oriented with respect to the workpiece (1) in a precisely positioned fashion. To move into the mounting position (29), an iterative closed-loop control process is run through, in the course of which firstly an (actual) measured value of the sensor system (18) is generated, which value is compared with a (setpoint) measured value which is generated within the scope of a setup phase.