With mergers & acquisitions playing an increasingly important role in today's business world, academic research has strived to follow this trend by investigating their underlying causes and consequences. For a long time this research focused on the analysis of the financial effect of mergers & acquisitions as measured by market value or debt level. Thus, despite being a major vehicle of industry concentration and method of reallocation of resources, the technological impact of mergers & acquisitions remained comparatively underinvestigated for a long time. This, however, has changed in recent years. With the prevalence of the resource-based view and its derivates as the dominant logic in analysing today's knowledge-intensive industries the focus shifted towards the technological aspects of mergers & acquisitions. With both mergers & acquisitions and innovation being centrepieces of competitive strategies in the modern economy, it is of central importance to understand the consequences of mergers & acquisitions for the innovative potential of firms. After more than twenty years of research in this field, it is time to take stock of what we know about the technological impact of mergers & acquisitions and its determinants. The aim of this paper is to provide an overview of the respective research by performing a meta-analysis of the empirical studies in the field. The intuitive setup allows for a detailed analysis of the individual determinants while differentiating between the impact on innovation input and output. We identify the knowledge characteristics of the partnering firms as being essential to the technological success of mergers & acquisitions. Important implications for policy makers, practitioners and future research are derived.