Wireless Body Area Networks (WBANs) are gaining significant attention because they can be very essential for the daily life applications in hospitals, schools, sports centers and gaming centers. In WBANs, reliability is a major factor that affects the system performance. Interference and inefficient routing can make a WBAN unreliable. However, an opportunistic routing technique can help to overcome the reliability problem. Conversely, the broadcast flooding uses all the available relays resulting in duplicate packets, longer delays and inefficient use of the network resources. We investigate by using the opportunistic routing with lognormal path loss model and IEEE 802.15.6 CM 3A. End-to-end (ETE) delay, network lifetime, packet delivery ratio and energy used per data packet are used as the performance metrics. The opportunistic routing improves the reliability of WBAN by 10 as compared to direct transmission. © 2013 IEEE.