Background Heart failure (HF), defined as a complex clinical syndrome that can result from any structural or functional cardiac disorder that impairs the ability of the ventricle to fill with or eject blood, is a leading cause of mortality and hospitalization for adults older than 65 years in the industrialized countries. The characteristics and outcome of patients with HF have been described by several epidemiological studies and large scale clinical trials, performed mainly in the United States and Europe. Very little information is available on this issue in Japan. Methods and Results The Japanese Cardiac Registry of Heart Failure in Cardiology (JCARE-CARD) is designed to prospectively study the characteristics, treatment, and outcomes of a broad sample of patients hospitalized with HF at teaching hospitals throughout Japan between January 2004 to June 2005 and the outcomes, including death and hospital readmission, will be followed through 2006 (mean follow-up at least 1 year). Participating cardiologists identify patients admitted for worsening of HF symptoms. Demographics, medical history, severity, treatment, and outcome data are collected and entered into a database via secure web browser technology. As of June 2005, baseline data for 2,676 patients with HF have been registered from 164 participating hospitals. Conclusions The JCARE-CARD will provide important insights into the management of patients with HF in routine clinical practice in Japan, thus providing the framework for improved management strategies for these patients. (Circ J 2006; 70: 1617 - 1623)