Objectives: To describe hospitalization rates and hospital morbidity among the foreign population residing in Aragon (Spain) by country of birth, between 2004 and 2007, and to compare these rates with those in the autochthonous population., Methods: A retrospective longitudinal study was carried out of hospital discharges of the foreign population in public hospitals in Aragon. Utilization rates were estimated by sex, age, country of birth and main diagnosis. Poisson regression was used to estimate the utilization rate ratios and their 95% confidence intervals., Results: Hospitalization rates were lower in the foreign population (adjusted RR: 0.52; 95% CI: 0.51-0.56), except in women aged between 15 and 24 years (RR: 2.9; 95% CI: 2.8-3.0) and among those born in the Maghreb (RR: 1.8; 95% CI: 1.7; 1.9), sub-Saharan Africa (RR: 2.0; 95% CI: 1.9-2.1) and Asia (RR=1.4; 95% CI: 1.3-1.6). When hospital discharges related to obstetrics and gynecology were excluded, only women born in sub-Saharan Africa continued to have adjusted RR greater than 1. These women had higher hospitalization rates in groups of infectious and parasitic diseases (RR: 2.5) and blood and blood-forming organs (RR: 2.8)., Conclusions: In Aragon (Spain), public hospital utilization is lower in foreigners than in the autochthonous population. The diseases treated varied by country of birth. The diseases prevalent in these countries, together with hereditary diseases, can increase hospital utilization rates., (Copyright © 2010 SESPAS. Published by Elsevier Espana. All rights reserved.)