The aim of this work was to devise, and assess the reliability, of an instrument to measure satisfaction with medical consultation of primary care urban patients at public outpatient clinics. A model was elaborated, based on data collected from the literature and from focal groups of patients and physicians, and an enquiry was developed and applied at four outpatient clinics. Fifty enquiries were obtained and analyzed to discard questions of difficult understanding. Next, a second self administered questionnaire and with fewer questions was devised. Its reliability was assessed in 53 enquiries, obtaining a Cronbach's a of 0.904. Questions that decreased consistency were discarded, finally obtaining a self administered instrument with 22 questions. This enquiry was used in 174 patients. Results were subjected to factorial analysis with varimax rotation, which separated three factors that explain 64% of the variance. It is concluded that a valid and reliable instrument was obtained.