There is no central control mechanism in Bluetooth and IEEE 802.11b to coordinate their communication behavior and prevent collisions between them. To combat the interference, Bluetooth just hops to another frequency and retransmits the collided packet, while 802.11b transmitters will back off for a while then retransmit the packet again. In general, a long packet is likely to be collided with more than a smaller one and it would take longer time to retransmit it. Consequently, packet segmentation of larger packets is of interest as a potential strategy on the part of 802.11b transmitters in the presence of Bluetooth. We evaluate the optimal packet size that could enhance the 802.11b throughput in the presence of Bluetooth. The results show that the performance increases substantially with appropriate segmented packet size compared to fixed payload.