Chronic patients suffer a greater number of health problems and have greater needs for assistance and care. The objective was to describe the use of health services in Primary Care in patients with chronic conditions according to risk level by adjusted morbidity groups (AMG) and analyze the associated factors.Cross-sectional study. We included patients ≥18 years-old identified as chronic by the stratification tool according to AMG in a basic health area in the Community of Madrid with an assigned population of 18,107 inhabitants. Sociodemographic, clinical-care and use of services variables were collected and were classified according to the "behavioral" model in predisposing, need or facilitators factors. Univariate, bivariate and multiple linear regression adjusted with robust estimators was performed.9,443 chronic patients (52.1% of the population in the selected zone) were identified, mean age of 57.8 (SD=18.7); 62.1% women. According to their risk level 4.7% were high risk, 18.7% medium risk and 76.6% low risk. The mean number of contacts per year was 14.1 (SD=15.2); 34.4 (SD=27.9) in high risk; 21.8 (SD=17.2) in medium risk and 10.1 (SD=10.2) in low risk. 7.5 (SD=7.1) contacts were with the doctor and 12.9 (SD=12.9) were face-to-face. The factors associated with higher use of services were high risk (Coefficient B[CB]=12.6; IC95%=11-14.2), immobilization (CB=8.8; IC95%=7.3-10.4), polypharmacy (CB=6; IC95%=5-8.6), female sex (CB=1; IC95%=0.4-1.5), number of chronic diseases (CB=1; IC95%=0.8-1.2) and age (CB=0.03; IC95%=0.01-0.05).The health services utilization in Primary Care in chronic patients is high and increased according with the risk level by AMG. The contact with the doctor is superior to nurse and the most frequent type is face-to-face. The greater utilization of services responds to predisposing factors (female sex and age) and above all to need factors (high risk, immobility, multimorbidity and polypharmacy).