Background: Patients enrolled in clinical trials continue to have frequent contacts with primary care physicians because of comorbidities or toxicities. The aim of the present study was to analyze the information provided at different levels, when participants are included in clinical trials organized at a specialized care level. The purpose was to verify if informing the patient's primary care physician is contemplated in the inclusion process. Methods:The authors conducted a cross-sectional study that included the clinical trials approved in the last 2 years by the hospital's Institutional Review Board. In addition, some of the participants in the included clinical trials were interviewed in order to check their knowledge of the type of research taking place. Results: In total, 67 protocols and the accompanying informed consent documents were reviewed. Half of the reviewed protocols (48%) did not provide participants with an identification card. Regarding the role of the primary care physician, 68.6% of clinical trials (46/67) had taken it into account in different ways. In only four trials, the method used to contact the primary care physician was documented. In total, 20 participants were interviewed. Only 3 (15%) knew the title of the study in which they were participating, 14 (70%) were aware of their illness and 6 (30%) did not know how to answer any of these two questions. Almost all participants in the study knew the name of the physician who was the principal investigator in the trial. Conclusion: Information given to health care practitioners, who are not directly involved in clinical trials conducted by specialized medical staff, is still scarce. In our clinical setting, patients participating in clinical trials have a low awareness of such studies.