RESUMEN
This paper assesses the quality of assistance in a clinical trial outpatient center as well as the patients understanding of the informed consent (IC); determine the reasons why they participate and detail socio-economic levels. A cross-sectional study was adopted in a clinical trial outpatient center using a self-explanatory questionnaire. All 100 respondents considered the assistance at the center excellent (86%) or good (9%). Almost all of them were well informed about the content of the IC. Their knowledge about the right to "confidentiality", present in all ICs, was 6 times higher than their knowledge about their right to "access the results", generally not included in the IC. The main reasons for participating were "to know more about ones health" (59%) and to "to benefit other people in the future" (47%). The participants income varied from 3 to 5 minimum wages (48%) and most (66%) concluded at least the 4th grade of basic education in Brazil. The subjects showed the economical characteristics of the average population of Rio de Janeiro. Their level of education allowed them to sign and to understand what they were signing. They were aware of the existence of the IC and its content. The main reason for participating was for one s own benefit and for the benefit of others.
