The internet exists as a global interconnection network for information sharing, commerce, and entertainment. The usage of internet has grown tremendously over the past decade in the field of E- health care monitoring system. In Ehealth care monitoring systems, Smart Wireless Body Area Networks (S-WBANs) is one among such technologies and is being explored. S-WBANs are primarily used as a smart object with computer-assisted rehabilitation. They serve as a remote monitoring service in smart electronic healthcare to continuously measure the vital parameters like heart rate, insulin level, body temperature, etc. They are thereby providing doctors with early detection of a patient’s medical conditions. However, sharing of sensitive personal data over a wireless network requires a high level of security. Since any breach in the system security will lead to a direct violation of the patient’s privacy. In order to address the security vulnerability of the existing system, in this paper a block chain based Smart Wireless Body Area Networks has been proposed to provide better security with enhanced privacy and access control for E- health care monitoring system. Moreover, the proposed system enhances the scalability and provides mitigation against all the security attacks in IoT Environment.