BACKGROUND: Our interest in chronic conditions is due to the fact that, worldwide, chronic diseases have overtaken infectious diseases as the leading cause of death and disability, so their management represents an important challenge for health systems. The aim of this study was to compare the performance of primary health care services in managing diabetes, congestive heart failure (CHF) and coronary heart disease (CHD), by age group. METHODS: This population-based retrospective cohort study was conducted in Italy, enrolling 1,948,622 residents ≥16 years old. A multilevel regression model was applied to analyze compliance to care processes with explanatory variables at both patient and district level, using age group as an independent variable, and adjusting for sex, citizenship, disease duration, and Charlson index on the first level, and for District Health Unit on the second level. RESULTS: The quality of chronic disease management showed an inverted U-shaped relationship with age. In particular, our findings indicate lower levels for young adults (16-44 year-olds), adults (45-64), and oldest old (+85) than for patients aged 65-74 in almost all quality indicators of CHD, CHF and diabetes management. Young adults (16-44 y), adults (45-64 y), the very old (75-84 y) and the oldest old (+85 y) patients with CHD, CHF and diabetes are less likely than 65-74 year-old patients to be monitored and treated using evidence-based therapies, with the exceptions of echocardiographic monitoring for CHF in young adult patients, and renal monitoring for CHF and diabetes in the very old. CONCLUSION: Our study shows that more effort is needed to ensure that primary health care systems are sensitive to chronic conditions in the young and in the very elderly.