The relationship of Christianity and philosophy is one of the enduring questions in Patristic studies. However, this question tends to be approached from an almost-entirely dogmatic perspective, leaving little room for studies of practice. This paper proposes to examine just such an issue, taking as its starting point one of the spiritual exercises in ancient philosophy expounded by Pierre Hadot, namely the practice of the examination of conscience. All the major schools of ancient philosophy, frequently drawing upon the Pythagorean tradition, encouraged regular and searching self-examinations in order to uncover occasions when adherents had failed to live up to their philosophical principles, and also when they had succeeded in living them out. In the Apophthegmata Patrum, a practice emerges which bears a number of close similarities to its philosophical predecessor, in such a way that an organic connection between the two seems likely. In particular, both the philosophers and the Desert Fathers suggest a morning as well as an evening examination, both advise examination of successes as well as failures, and both promote practices whereby the results of examination are externalized, either through confession or writing. The purpose of this paper is twofold. First, it aims to explore the practice of self-examination in ancient philosophy and Christian monasticism, tracing the developments and modifications it undergoes as it moves from one context to another. Second, the paper seeks to help broaden the conversation about the relationship of Christianity and philosophy, one that includes elements of practice as well as doctrine.