The study is to compare the thought and praxis of repentance between Catholicism and Buddhism. Repentance, one of the areas common to world religions, is an expression of guilty consciousness of criminal subject. Religious sins occur mainly because of offending commandments or precepts, morally misbehaving or violating doctrines. There are similarity and uniqueness among religions. Catholicism and Buddhism have different concepts about universe, as well as God and precepts which affect the formation of sense of guilt and then affect the thought and praxis of repentance. For Catholicism, God is the Creator of the world, and He is the object penitents offend and show repentance to. And only God Himself can forgive penitents. Through the priests and the Sacrament of Repentance, penitents reconcile with God and the Church. For Buddhism, the world was formed through cause and condition, and the lives will be reincarnated. Because of self-attachment (ātma-grāha), Dharma-attachment or violating the precepts, there occur vexations and karma. To reduce karma, penitents need to repent in time. The penitents show repentance to Buddha or buddhas. According to the precepts obeyed and different situations, various repentant methods are performed. The similarity and uniqueness of repentance between the two religions are presented after comparison. The main similarities of repentant thought and praxis are as follows: parts of them are originated with the former religion, precepts are their important base, they match for spiritual exercise, there exists a trend of changes from public to private repentance in the historical development, there are practices in plural rituals, and religious experiences with hope and progress to gain eternal happiness. The main differences are the authority to forgive, one or plural ways to forgive great or mortal sins, the generality of repentant ritual, the necessity of confession, satisfaction or parināma, the innovation of repentant performance in China, and the insight of life.
