This study is aimed to describe what benefits and costs volunteers of the Spanish Association against Cancer (aecc) perceived, as well as analysed what barriers they observe thatban people to be a volunteer. Fifty-eight volunteers participated on this study. A questionnaire was used asking benefits and costs they extract form being a volunteer, and what limitationspeople could have for not being a volunteer. Results show that volunteers expressed more benefits than costs, and that the cost most frequently mentioned was the lack of flexibilitysome activities have. Lack of time and the need of more information were the two barriers most valuated. Differences between assistance and non-assistance volunteers were found on costs and benefits, and differences between age of volunteer on barriers perceived. Results are discussed through what improvements organizations could do in order to manage volunteers that work in cancer’s situations more efficiently. CITE AS:Celdrán Castro, M. & Buscemi, V. (2011). Beneficios, desventajas y barreras para ser voluntario: percepción de los voluntarios oncológicos. Apuntes de Psicología, 29, 59-70.