With the present paper we set out to create and validate an instrument designed to evaluate the satisfaction with the health services- referred to the most general aspects of them- for users and services of institutions of the third level of care of the National Health System of Cuba, the instrument allows an individualized approach to the study of satisfaction, referred to its most subjective aspects from the perspective of the own users. The study included patients and relatives from two institutes of the third level of care. For the creation and validation of the instrument, methods and procedures described to these ends and completely updated were used. The current version of the resultant questionannaire ( In Spanish CESUSS) is formed by 25 items and it proved to be a valid and reliable instrument for the purposes it was designed.