Background: Geriatric patients have significant morbidity and greater needs for care and assistance. The objective of this study was to describe the characteristics, morbidity, and use of services in primary care (PC) of patients with chronic diseases older than 65 years according to their risk level assigned by the adjusted morbidity groups (AMG) and to analyse the factors associated with the use of PC services.Methods: This was a cross-sectional descriptive observational study. Patients older than 65 years from a basic health area, classified as chronically ill by the AMG classification system of the PC electronic medical record of the Community of Madrid, were included. Sociodemographic, clinical-care, and PC service utilization variables were collected. Univariate, bivariate and multivariate analyses were done.Results: A total of 3,292 chronic patients older than 65 years were identified, of whom 1,628 (49.5%) were low risk, 1,293 (39.3%) were medium risk and 371 (11.3%) were high risk. Their mean age was 78.1 (SD=8.1) years and 2,167 (65.8%) were women. Their mean number of chronic diseases was 3.8 (SD=2), 89.4% had multimorbidity and 1,550 (47.1%) were polymedicated. The mean number of contacts/year with PC was 19.5 (SD=18.2) [men: 19.4 (SD=19.8); women: 19.5 (SD=17.4)]. The mean number of contacts/year in people over 85 years was 25.2 (SD=19.6); in people 76-85 years old, it was 22.1 (SD= 20.3); and in people 66-75 years old, it was 14.5 (SD=13.9). The factors associated with greater use of services were age (B coefficient [BC]= 0.3; 95%CI= 0.2 – 0.4), high risk level (BC=1.9; 95%CI =0.4 – 3.2), weight of complexity (BC=0.7; 95%CI=0.5 – 0.8), and ≥ 4 chronic diseases (BC=0.7; 95%CI=0.3 – 1.1).Conclusions: In the geriatric population, we found a high number of patients with chronic diseases and there were three levels of risk by AMG with differences in characteristics, morbidity, and use of PC services. The greatest use of services was by patients with older age, high risk level, greater weight of complexity and ≥ 4 chronic diseases. Further research is needed to develop an intervention model more adapted to the reality of the geriatric population based on risk levels by AMG.