This study examined how health professionals signify the religiosity and faith of patients under cancer treatment and how they themselves experience such phenomena. This is a qualitative-descriptive study, using the phenomenological framework as set out by Stein and Ales Bello, as a way of understanding the human being in its totality - physical, mental and spiritual. Most professionals report they are spiritualists, two are Catholics, one physician is a Buddhist and another is a Spiritist. They believe that religion is inherent to all human beings. Professionals convicted of their religion (less than half) believe in divine protection and recognize religiosity as a support and comfort for patients and their families in coping with illness. They expect patients to live their faith with prudence, never losing sight of reality.