Polish musicologists have been interested in the musical culture of religious institutions in Kraków during the 17th and 18th centuries since at least the beginning of the 20th century, but up to now the musical life of the monastery belonging to the Brothers Hospitallers of St John of God was of no interest to them. The main aim of this article, based on archival sources, is to show when and what kind of music was performed in this monastery, who the musicians were and what instruments were in the church. It has been established that the Brothers Hospitallers did not have their own musical ensemble, but rather that they invited musicians from the city, including from a Jesuit ensemble, who added splendour to the most important celebrations of the liturgical year by playing masses, litanies, passions and requiems. The research has also discovered that there was a positive organ in the Brothers Hospitallers’ church, and a harpsichord in their Hospital, the sounds of which made the patients’ time there more pleasant.