Background. Advance care planning (ACP) and goals of care discussions involve the exploration of what is most important to a person to prepare for health-care decision-making. Despite their well-established benefits, they are still not frequently performed in clinical oncology practice. The awareness of physicians’ barriers enables the development of tailored interventions to improve professional practice. Considering the scarcity of studies about the difficulties of medical residents in discussing goals of care, this study aims to determine, from the perspective of medical residents, the barriers to the discussion goals of care and ACP with patients with cancer. Methods. A previously published survey (Decide-Oncology) to assess barriers to goals of care discussion among health care providers was adapted to Portuguese language and distributed to Brazilian medical residents from three hospitals in Brazil in a cross-sectional pilot study. Residents were asked to rank the importance of various barriers to discuss goals of care (ranging from 1-extremely unimportant to 7-extremely important). Results: Twenty-nine residents answered the questionnaire (30.9%). The most reported barriers were related to patients and their families' difficulty in understanding and accepting the diagnostic and the prognosis, patients’ desire to receive full active treatment and the lack of an advance directive. Furthermore, the physician and external factors such as lack of training and lack of time to have these conversations were also very important barriers. The identification of the key barriers that limit the discussion of ACP and early palliative care referrals can certainly help to prioritize the next steps for future studies aimed at improving ACP and goals of care discussions.