As in other areas of social engineering, Sweden is considered as world-leading in creating systems that address social inequality. One of the cases in point is the Swedish day-fine system which has been considered as pioneering by systematically considering both the wealth of the offender and the seriousness of the offence when imposing the penalty. This chapter analyses in detail the Swedish day-fine system. The case study of Sweden sheds light on the pros and cons of day-fines by recalling the discussion in Sweden prior to introducing the system and the recent academic debates on extending the use of day-fines. The chapter also offers an account of the comprehensive prosecutorial guidelines as well as an analysis of the relevant case law, particularly in relation to adjustment of day-fines. The chapter argues that the Swedish day-fine system overall must be considered as a largely successful project which holds high esteem among courts and practitioners. The common view is that it is a merit of the system that it forces the courts to consider the economic circumstances of the accused and to articulate openly for the way in which such consideration has been done.