To study the incidence, main causes, aggravating factors and secondary diagnoses of heart failure (HF) during 1995 at the Instituto do Coração of São Paulo. Data from hospitalized patients according to the PRODESP data base were analyzed. The following data were studied; age, sex, principal and secondary diagnoses, surgical procedures and mortality. To analyze the data, tables according to sex, age and main cause were built. Analysis of variance and t test were employed to verify differences between groups. In 1995, 903 out of 9620 patients were hospitalized due to HF. The majority were male (60.4%) and the patients' age was between two days and 98 years old (mean 52.6). Ischemic (32.6), dilated (25.8%) and valvar heart disease (22%) were the main causes of HF. 32.1% were submitted to correction of the HF main cause, specially those with valvar heart disease (62.3%). There was greater incidence of multiple diagnoses in aged patients. The mortality was greater in patients younger than 20 and in those older than 80 years old. The incidence of HF at INCOR during 1995 was 9.38%. Ischemic myocardiopathy was the most frequent HF cause. The mortality was greater among children, probably because of heart disease complexity and, in the above-80 group due to the greater comorbidity.