Mergers & Acquisitions (M&A) has almost become an emotive phrase in academic research and business practice in recent years, especially due to the large number of studies that report on their failure. One of the most prominent reasons for the low success rate of M&A transactions is the insufficient involvement of employees in such transactions. Although in recent years human resource issues have increasingly been addressed in M&A due diligence, the specific employee competence requirements that ensue from M&A transactions have to date hardly been investigated in academic research and business practice. Daniela Peterhoff develops a concept for Human Resource Due Diligence (HRDD) in M&A that addresses the context-specific employee competence requirements resulting from such transactions. In developing her concept, the author presents a three step HRDD process. In step one she develops focus areas for HRDD based on the objectives underlying an M&A transaction. The second step shows how the HRDD information identified as relevant in step one can be generated. The author develops indicators to break down employee competences, and identifies valuation tools through which these indicators can be assessed. In the third and final step, she compiles the HRDD information generated in step two based on controlling ratios and human resource portfolios.