In John Kingdon's Policy Streams Approach policy formation is described as the result of the flow of three 'streams', the problem stream, the policy stream and the politics stream. When these streams couple, a policy window opens which facilitate policy change. Actors who promote specific solutions are labelled policy entrepreneurs. The aim of this study was to test the applicability of the Policy Streams Approach by verifying whether the theoretical concepts 'policy windows' and 'policy entrepreneurs' could be discernable in nine specified cases. Content analyses of interviews and documents related to child health promoting measures in three Swedish municipalities were performed and nine case studies were written. The policy processes preceding the municipal measures and described in the case studies were scrutinized in order to find statements related to the concepts policy windows and policy entrepreneurs. All conditions required to open a policy window were reported to be present in eight of the nine case studies, as was the most important resource of a policy entrepreneur, sheer persistence. This study shows that empirical examples of policy windows and policy entrepreneurs could be identified in child health promoting measures in Swedish municipalities. If policy makers could learn to predict the opening of policy windows, the planning of public health measures might be more straightforward. This also applies to policy makers' ability to detect actors possessing policy entrepreneur resources.