In this article, we explore the determinants of reforms intending to integrate policies and coordinate administrative units by focusing on necessary conditions. Firstly, we elaborate theoretical expectations about potential necessary conditions for cross-sectoral reforms. Secondly, we conduct a condition-oriented fuzzy-set qualitative comparative analysis to examine our expectations, based on an original data set comparing policy integration and administrative coordination reforms, in environmental and unemployment policy, across 13 countries over 29 years. Our results indicate three necessary conditions for high reform intensity: external problem pressure is necessary for policy integration and administrative coordination in employment policy; either the strength or weakness of the reference party can take the role of necessary conditions depending on the policy field; low politicization of bureaucracy is necessary, especially for administrative coordination in environmental policy. These findings contribute to the development of a systematic theory of cross-sectoral policy and administrative change.