For municipalities to address challenges that come alongside a population decrease, inter-municipal cooperation is seen as an effective measure but, as this thesis shows, it comes not without a cost. This essay's thesis strives to investigate in what ways inter-municipal cooperation affects democratic legitimacy. To do so, a document analysis is applied on a large number of different relevant documents such as audit reports, annual reports and board minutes. The documents are analyzed through a lens of three legitimating dimensions, input, throughput and output. The analysis results in several interesting observations. Firstly, by being part of a joint committee, the municipality receives a lower input-value. Secondly, there are tendencies that when entering inter-municipal cooperation, the operation becomes less transparent and thereby obtains a low throughput-value. Thirdly, there are weak tendencies that inter-municipal cooperation causes the operation to work somewhat more efficiently and will thereby obtain slightly higher output-value. The analysis concludes that yes, the democratic legitimacy does get affected by inter-municipal cooperation, but whether it is for the better or worse depends on the individual trade-off between the values.