Most of the population in America suffers from chronic diseases that require constant medical supervision; America today is plagued by the national crisis of inadequate and expensive healthcare. Timothy Wirth, President of United Nations Foundation with regards to mHealth and Mobile Telemedicine Conference in 2008 was quoted saying "Modern telecommunications and the creative use of it has the power to change lives and help solve some of the world's biggest healthcare challenges, mainly access and affordability." To that extent, this thesis introduces the architecture of a multi-tier telemedicine system comprised of strategically placed bio-sensors on a human body (thereby forming a Wireless Body Area Network or WBAN), capable of collecting vital medical statistics such as heart rate and blood pressure. The data collected will be transmitted wirelessly to a personal wireless hand-held device akin to a cell phone. Data will be further transmitted to a medical server designed to store a patient's medical record at a caregiver's location either through multiple wireless technologies or through wires or both thus guaranteeing ubiquity, mobility and personalization of service thereby taking telemedicine (often defined as "medicine at a distance") from the desktop to "roaming". However, fundamental wireless networking issues must be addressed and resolved before this dream can be realized. Generic approaches to prolong network life in a wireless sensor nodes involves techniques like over provisioning-an approach inapplicable of application to sensors in a BAN where extra sensors might not be implanted on a human body. Furthermore, critical biological data should be given the highest Quality-of-Service (QoS) guarantee. Moreover, when critical biological data -- referred to in the thesis as "Emergency Date or ED"- compete for network resources with not-so-critical biological data - referred to in the thesis as "Non Emergency Date or NED"- of some other sensor of the same BAN, appropriate priority assignment and scheduling schemes are required to make the application fruitful. However, issues, concerns, and requirements inherent to the telemedicine application have not received adequate attention. This thesis aims to research two fundamental Medium Access Control (MAC) functionalities: (a) energy efficiency and (b) Quality-of-Service (QoS) guarantees in terms of traffic prioritization and scheduling, tailor made for a personalized, mobile, and ubiquitous telemedicine application. This thesis proposes a novel Medium Access Control (MAC) protocol which guarantees the timely delivery of critical Emergency Data(ED) without sabotaging the throughput requirement of Non-Emergency Data (NED). Moreover the protocol also takes into account the desired feature of minimal energy consumption of the bio-sensors. The MAC layer protocol is developed and tested on the network simulation platform -- NS2. The performance of our MAC in terms of throughput, delay constraint adherence and energy efficiency is compared with another popular IEEE standard MAC -- 802.15.4. We chose IEEE 802.15.4 as our benchmark because existing research on WBANs have championed IEEE 802.15.4 as the most appropriate technology for a WBAN application. Simulation results and performance analysis and comparison demonstrates that our protocol is better suited for the purpose of WBAN applications when compared to IEEE 802.15.4.