The article addresses the problem of the functioning of secular clergymen in the castles of the Teutonic Order in Prussia. Brother priests were to run the religious life of the convents, but there is sufficient evidence showing that non-Teutonic clergymen were also employed to do this job. This group belonged to the category of “servants” (gesinden). It included chaplains of Teutonic officials, chaplains serving in the choir, vicars in infirmaries, deacons, sub-deacons, ringers and alumni. They played auxiliary functions in relation to brother priests, the shortage of whom may be noticeable in the first half of the 15th century. Secular clergymen helped to say the canonical hours in the castle’s choirs; however, they acted also as chaplains and notaries of Teutonic commanders, Pflegers or Vogts. They received remuneration for their work for the convents – both in the form of money and maintenance in the castle. Nevertheless, not all secular clergymen lived in the castle. Some of them owned prebendaries in the vicinity of the castle and treated their service in the castle as extra work, which not only provided them with additional income, but also facilitated the career development – as it is indicated in the recommendations of Teutonic officials to take over prebendaries. The service in the castle was often the preliminary step to become a member of the Teutonic Order.