The use of electronically stored data requires that the data is recorded in a structured and standardized manner. This has led to the development of terminological systems. The content of these medical terminological systems is subject to continuing changes as a consequence of the developments in the field of medicine.By means of a literature study criteria were obtained for the maintenance of terminological systems. The criteria are used to develop a framework for the management of the maintenance process. The current practice of terminology maintenance was explored in a survey of twenty-seven organizations that currently maintain a terminological system. The results of the survey reveal the diversity and suboptimality of the current maintenance processes. The framework for the management of the maintenance process can be used to eliminate deficiencies in this process. This framework for terminology maintenance is an important step towards standardization of the maintenance of medical terminological systems.