Examination of conscience is a review of one's past thoughts, words, actions, and omissions for the purpose of ascertaining their conformity with, or deviation from, the moral law. Among Christians, this is generally a private review; secular intellectuals have, on occasion, published autocritiques for public consumption. In the Catholic Church, penitents who wish to receive the sacrament of penance are encouraged to examine their conscience using the Ten Commandments as a guide, or the Beatitudes, or the virtues and vices. A similar doctrine is taught in Lutheran churches, where penitents who wish to receive Holy Absolution are also asked to use the Ten Commandments as a guide. The process is very similar to the Islamic practice of Muhasaba, or self-reflection.

"The excellence of this practice and its fruitfulness for Christian virtue," preached Pope Pius X, "are clearly established by the teaching of the great masters of the spiritual life." St. Ignatius of Loyola considered the examination of conscience as the single most important spiritual exercise. In his Spiritual Exercises he presents different forms of it in the particular and general examination (24-43). Of the general examination he writes; "The first point is to give thanks to God our Lord for the favors received" (43). This point has become a highly developed part of Ignatian spirituality in modern times, and has led to many more positive practices, generally called examen of consciousness. In twice-daily "examens" one might review the ways God has been present through one to others, and to oneself through others, and how one has responded, and to proceed with one's day with gratitude, more aware of the presence of God in one's life.

In general, there is a distinction between the particular examen, which aims to change one particular feature or defect in one's behavior, the examen of consciousness, which is a more nuanced reflection, and the general examination of conscience as used before the sacrament of penance.” This last method is called examination of conscience because it is a review of one’s actions from a moral point of view, reflecting upon one’s responsibility and looking at one’s sins and weaknesses in preparation for repentance, in contrast with the examen of consciousness which does not focus on morality even if sins will emerge during the review of the day.