This article focuses on the role of local municipalities in detecting and sanctioning benefit fraud, specifically fraud with social assistance benefits. Since the early 2000's, the government's attention for benefit fraud has been increased, resulting in the strengthening of the tasks and responsibilities of local municipalities in combatting and detecting fraud. There are indications that this has been successful: there is an increase in detection and the number of people that claims to offend the rules is decreasing. However, there is a significant amount of variety between municipalities in their performance with this regard. The authors argue that these differences are related to the design and implementation of local policies concerning the detection of benefit fraud. They offer several recommendations for more effective policies at the local level. These recommendations include a better use of available data and knowledge about the background of offenders and social assistance recipients.