Information Communication Technology (ICT) has become an essential component in healthcare because it enhances interoperability amongst healthcare practitioners by facilitating the seamless and meaningful exchange of information within and across diverse healthcare institutions at the point of care. Consequently, healthcare providers have timely access to patients' information which enables them to manage patients' health in a timely manner. However, interoperability amongst electronic healthcare systems is still a challenge. One of the major obstacles to interoperability of electronic health systems is the problem of usability. Specifically, the ability of healthcare providers to accept and use electronic healthcare systems for information exchange successfully depends on how well the user interface of the electronic healthcare systems have been designed. Thus, a poorly designed user interface, missing critical functionalities in the electronic healthcare system or an inadequate match between the features of the user interface and the user tasks contributes to medical errors, decreased user performance and satisfaction as well as inefficient healthcare such as missing information important to diagnoses. Consequently, healthcare practitioners find it difficult to accept and use electronic healthcare system for patients' care and meaningful information exchange. Hence, this paper appraises the impacts of usability on the interoperability of electronic healthcare systems. The paper also examines the ways of ensuing usability amongst interoperating electronic healthcare systems.