INTRODUCTION: Morbidity and mortality associated to the respiratory syncytial virus (RSV) disease induce costs presumed important. The assessment of the macro-economic impact of the infection is for one part based on the knowledge of the epidemiological data and further on the evaluation of the cost of the infected patient. Following the WHO, the world annual incidence would be 60 to 65 million cases. The proportion represented by the elderly is little documented. Nevertheless, because of an upcoming interest in the health sector for diagnostic and prophylactic treatment, new data appear and make appear the RSV as an emerging pathology. The incidence of RSV infections with the elderly could be 5 to 10% in the winter. In the non-institutionalised patient, the hospitalisation probability for complication is estimated, according to publications, to 1 to 5%. However, for the subject with a risk factor, (heart and respiratory failure) the respiratory infection probability is 4.3%, inducing hospitalisations in 37% of cases. RESULTS: Direct costs were calculated as the sum of costs due to medication, consultations, hospitalisation and respiratory physiotherapy. The impact of indirect cost should also be taken into consideration. Our estimation evaluated them four times inferior to those due to influenza. With regards to the risk of hospitalisation (1%-3% or 5%), the average cost of RSV infection varies, according to a societal perspective, from 750 to 1103 Euros. CONCLUSION: The annual financial burden of RSV disease from the payer perspective would be between 306 to 612 millions Euros. This annual figure represents a third of the cost allocated to influenza, which justifies the efforts of research in view of making emerge a vaccine against the RSV.