A society without an institution which takes care of the probation service would be inconceivable. In Austria the organization NEUSTART is responsible for the probation service. Due to the fact that the work of a probation officer is of high importance, this thesis covers the obligation to confidentiality of professional and voluntary probation officers. The mentoring is only worthwhile if there is a basis of trust between the probation officer and his client, therefore in the context of probation service the obligation to confidentiality plays a very important role. At the beginning of this thesis the terms secret and discretion will be discussed in general. In addition, an overview of the probation officer, his work and the differences between a voluntary and a full-time aide are given. Moreover, the concept of probation service and its meaning and purpose is explained.The third chapter deals with the obligation to confidentiality in more detail. Within the framework of the probation service two kinds of probation officers and their obligation to confidentiality have to be differentiated: the governmental probation officers with a special status and the voluntary respectively full-time probation officers. In a further step the consequences of the violation of the obligation to confidentiality are discussed. Again, a distinction between the two possible kinds of probation officers is made. In the next chapter a possible right to press charges, the obligation to press charges, which should be considered, and the obligation of prevention are explained. Finally, I refer to the probation officer as a witness in a criminal proceeding and explain this topic in more detail.