We demonstrated all-optical label storing and switching for 40 Gb/s optical packets by using all-optical signal processing of multimode interference bistable laser diode optical flip-flops. The stored optical labels in the optical flip-flop controlled an all-optical switch to forward the injected optical packets. The 40 Gb/s optical packets were successfully switched in the all-optical scheme with 11-dB extinction ratio. Error-free operation for the output packets from the switch was also obtained with 1.3-dB power penalty. The presented all-optical packet switching has the advantages of ultrafast switching and transparency of data rate and format, suitable for the future optical networks.