Heart failure is a common, costly condition characterized by recurrent periods of clinical decompensation that often lead to rehospitalizations. Periodic, often infrequent, outpatient visits are the only usual opportunities for providers to detect and treat early signs of heart failure decompensation - this constitutes a major gap in the current medical model. Moreover, occasions for patients to take an active role in managing their own conditions are rare. Telemonitoring, which uses electronic and communication technology to bridge distances between physicians and patients, holds promise for closing the gap in heart failure care. However, little rigorous assessment of the effectiveness of telemonitoring has been conducted. We will examine a telemonitoring strategy that facilitates communication between patients and health care providers and the general education of patients about managing their conditions. This strategy uses the Health Buddy(r) system, which connects to conventional telephone lines and does not require Internet access. While many vendors have potential tools to implement this study, we have chosen to use the Health Buddy(r) system because it is representative of telemonitoring appliances currently available and preliminary data are available to suggest high patient and provider satisfaction with its use. We will determine whether use of this strategy for 6 months, added to usual medical care, reduces rates of all-cause readmission in patients who had been hospitalized for heart failure in the previous 30 days. We propose a multicenter, randomized controlled trial, recruiting 1,640 patients from community-based cardiology practices across the United States that are eager to participate. Providers from the local practice sites will review and act upon information from the telemonitoring appliances. If the intervention is effective, we will have implemented an economically attractive disease-management strategy that can be standardized, integrated into the current system of care, and deployed on a wide scale, with potential for dramatic improvements in outcomes of heart failure patients.