Data interoperability is a key ingredient for modern health information technology. Interoperability of healthcare information systems is essential for the communication of critical data, as well as for leveraging the vast amounts of data gathered to conduct research, analyze trends, improve safety, and reduce healthcare costs. One of the critical components for enabling interoperability is the availability of data standards. This paper presents, from a practitioner’s perspective, a broad overview of the current status of healthcare data standards and an analysis of the problems with current standards including gaps, redundancies, and varying data exchange requirements that prevent seamless data exchange between healthcare information systems. This paper concludes by identifying problems related to healthcare information systems standardization and interoperability and potential issues for future research that can address the given problems.