An automatic suturing instrument generally includes a proximal actuation handle assembly, a flexible tubular member, a control wire, and an end effector assembly. The control wire extends through the tubular member and the end effector-assembly is coupled to the distal end of each of the tubular member and the control wire, while the handle is coupled to the proximal end of each of the tubular member and the control wire. Actuation of the handle moves the control wire relative to the tubular member and thereby moves the end effector assembly from an open to a closed position. The end effector assembly generally includes two end effectors, a needle engaged by one of the end effectors (but which can be engaged by either end effector alternately), and a suture material. The end effector assembly further includes a needle passing mechanism that automatically alternates which end effector engages the needle each time the end effectors are moved into a closed position.