Heart failure (HF) is a health problem that particularly affects the elderly population. Its onset is associated with other chronic diseases, a circumstance that makes it a challenge for health care services. The aim of this study is to quantify the prevalence of HF in family medicine offices and describe the chronic co-morbidity associated with it. A cross-sectional, observational descriptive study set in a health area of the Community of Madrid, Spain. The study was carried out in a population of 198,670 individuals over 14 years of age, attended to by 129 specialists in family medicine. The patient was considered to have HF when this diagnosis (ICPC code K77) appeared in his or her electronic medical record. The prevalence of HF was quantified and its association with another 25 chronic diseases was analysed. The prevalence of HF was 6.9‰, 7.9‰ among women and 5.9‰ among men. Patients with HF had a high rate of chronic co-morbidity, with an average of 5.2 + 2.1 chronic diseases. Only 3% of the patients present with isolated HF and >60% have four or more additional chronic problems. Hypertension, cardiac arrhythmias, hyperlipidaemia, obesity and diabetes mellitus are the chronic diseases most frequently detected in HF patients. Patients with HF frequently visit the offices of family physicians, presenting with a high rate of cardiac and non-cardiac co-morbidity that proves to be a challenge on the clinical level and in terms of the organization of health care services.