The two battles for Fallujah took place in 2004. Earlier research states that air power was a key reason for the success following the second operation, and as a critical omission during the first operation. Following this statement that air power changed the way urban operations should be conducted it should be possible to use an air power theory to explain the different outcomes of the battles. The purpose of this study is to see if Robert Pape’s theory of denial strategy is applicable as an explanation for the two operations differences of outcome.   The method used for this study is a comparative case study of the two operations in which the operations are compared by analysing then using the framework of Pape’s theory.    The result of this study shows that the outcomes partly can be explained from Pape’s theory, but the results differ between the two components which leads to a discussion of what this means for the theory. The result contributes to the existing research and gives reason for criticism of the earlier research which states that it was Close Air Support (CAS) that was successful during the second operation. This study shows that CAS was mostly used during the first operation and only partly used during the second, successful, operation. This study states that it was the use of operative interdiction, one of the three components of Pape’s theory, which led to the second operations success.