Bettina Hauser develops a research model, which encompasses entrepreneurial leadership as a major success factor during post-merger integration. Additionally, contextual variables, namely cultural distance and the organizational variable, relative size, are tested for their moderating effect on the influence of entrepreneurial leadership on M&A performance. The author clarifies the question of how entrepreneurial leadership can help to enhance M&A performance. Based on 114 transactions with acquirers of German-speaking companies, she proves that entrepreneurial leadership has a positive effect on post-acquisition performance and helps to overcome problems related to cultural differences.  Contents Mergers & Acquisitions – State of the Art: M&A Basic Concepts, Cross-Border M&A, National vs. Organizational Culture, Post-Merger Integration, Problem Statement Research Model and Hypothesis Development Methodology: Measurement Development, Sample and Data, Results Discussion: Managerial and Theoretical Implications, Limitations and Future Research  Target Groups Researchers and students in the fields of International and Strategic Management as well as Business Development M&A Managers, CEOs and Human Resource Managers  The Author Bettina Hauser obtained her Master of Arts degree at Management Center Innsbruck (International Business and Law), Austria. She is specialized in the field of International and Strategic Management.