The continuing epidemics of diabetes and obesity create much need for information technologies that can help individuals engage in proactive health management. Yet many of these technologies focus on such pragmatic issues as collecting and presenting health information and modifying individuals’ behavior. At the same time, researchers in clinical community argue that individuals’ perception of their identity has dramatic consequences for their health behaviors. In this paper we discuss results of a deployment study of a mobile health monitoring application. We show how individuals with considerable diabetes experience found a unique way to adopt this health-monitoring application to construct and negotiate their identities as persons with a chronic disease. We argue that viewing health management from identity construction perspective opens new opportunities for research and design in technologies for health.