IN-CHF is a multicenter registry, designed in 1995 to compile a large clinical database on the epidemiological, clinical characteristics, management and outcomes of heart failure outpatients. Main objectives of IN-CHF registry were to provide cardiological centers with a software to collect data of outpatients during office visit, for educational purpose; and to enter local data into a national registry (IN-CHF registry), for scientific purpose. Entry into the database required a diagnosis of heart failure according to the guidelines of the European Society of Cardiology. The central coordinator of the project was the ANMCO Research Center. The Italian cardiological centers participating in the project are 142, they are well representing the entire country and from March 1995 to July 2005 collected data from 23 855 outpatients. The mean age of the patients was 65+/-13 years and 71.3% were men. Main etiologies were ischemic in 39.4%, hypertensive in 15.8 %, and due to dilated cardiomyopathy in 29%. More than half of the patients (55.3%) had a history of admission for heart failure within the last year; 25.8% of the patients were in NYHA class III-IV, 9.5% showed a heart rate > 100 bpm and 16.5% third heart sound. Left ventricular ejection fraction was severely depressed (< 30%) in 27.6% of the patients, while it was > 40% in 30.9%. Renal dysfunction was present in 3.6% of the patients (serum creatinine level > 2.5 mg/dl), pulmonary disease in 18.7%, diabetes in 16.8% and anemia (hemoglobin < 12 g/dl) in 18.7%. A history of arterial hypertension was common (30.3%); 20.0% and 18.5% of the patients showed atrial fibrillation and left bundle branch block, respectively. Data from our registry provide important insights into clinical and epidemiological characteristics of heart failure outpatients followed in Italian cardiological centers. Starting from this article, every 3 months, the most relevant epidemiological data collected by the IN-CHF investigators will be published.