Background: Secondary transfers of critical patients between hospitals may be associated with risk of death and complications Aim: To determine the risk profile of adults subjected to secondary transfers using the Emergency Medical Attention System (SAMU) operating in Metropolitan Santiago. Material and Methods: Cross sectional study including 432 adults undergoing secondary transfers using SAMU between January 1 and June 30 2010. Demographic, biomedical, hemodynamic and transfer data were obtained. Cardiopulmonary arrests (CPR) and an increase in the Rapid Emergency Medicine Score (REMS) scale, were considered as outcome variables. Results: CPR occurred in 6.4% of the study population and was significantly associated with the initial REMS score and the need for hemodynamic and ventilator support. The initial REMS score was a good predictor of the final REMS score. The final REMS was significantly associated with the presence of comorbidities and the need for hemodynamic and ventilator support. Conclusions: REMS is a useful scale to assess the risk profile of critical patients requiring transfers between hospitals. (Rev Med Chile 2012; 140: 1297-1303).