Every year some 90% of 15-year-olds in Finland attend confirmation classes in the Evangelical Lutheran Church of Finland, which is greater than the percentage of that age group belonging to the Church. What is behind the popularity of Finnish confirmation classes? This article scrutinizes the quality and effectiveness of confirmation classes. Classes and their quality are approached from three angles: (1) equivalence of confirmation expectations and experiences; (2) participants' satisfaction; 3) effectiveness of confirmation classes. As its theoretical basis the study leans on the quality of service thinking typically used in market research. The study is based on questionnaire data gathered from young people (n = 1109-1322) before and after participating in confirmation classes. Response rates were 90 and 76%. The findings of the study show that there is no contradiction between the three perspectives of the quality of confirmation classes: those classes for which satisfaction was reported and in which expectations and experiences were fulfilled or exceeded were also those which had the most positive effects on attitudes to Christianity. (Contains 8 tables.)