This document analyzes the access to health services for the population belonging to the contributive and subsidized regimes in the Colombian Caribbean region. Models of discreet selection are constructed - simple logit and Heckman probit - to gain insight about the determinants for the use of health services because of both preventive and curative reasons. Among the main results were that while the difference in the probability of access for the affiliated is very important in the case of use of the services because of prevention, this difference does not exist in the case of hospitalization. This suggests severity of the disease reduces the access difference to health services of the non affiliated with respect to those belonging to any regime of affiliation.