Objectives : To design and implement a shareable consumer health record system to investigate whether the system can assist in the management of chronic diseases. Methods : A toolkit was designed for constructing the consumer health record system in an evolutionary way. An ethnographic-like approach (formative evaluation) was used to let users (patients and care providers) assess the system leading to incremental changes in the system. Results : The evaluation provided us with sufficient information about which parts of the system needed adaptation. The final consumer health record system was well accepted by patients and care providers. The system is Web-based and is used at home by patients having diabetes. Both care providers and patients enter data. The system can download the data from a glucose meter. It provides feedback to patients on the basis of entered data and incorporated guidelines. It also allows discussion forums. Conclusion : Formative evaluation is useful for obtaining feedback from users about prototype systems. Care providers and patients together worked with the consumer health record. Both parties appreciated the system. The approach described here can be used for developing systems for other chronic patient groups.