Mergers and acquisitions can be a mechanism used by firms to access innovative knowledge, including intellectual property, and to strengthen and expand their core capabilities. In the mergers and acquisition context, the creation of value depends on the transfer of capabilities and knowledge being carried out successfully during the post-acquisition integration process. The paper adopts this view. It examines the role of the top management and personnel who hold knowledge and skills linked to the capability of the acquired firm considered most valuable by the acquiring firm in the transfer of knowledge from the acquired firm to the acquiring firm. The paper also examines whether the impact of the retention of the acquired firm's high-value human resources (HVHR) on knowledge transfer is moderated by the degree of embeddedness of the knowledge to be transferred. Furthermore, the study identifies the factors that influence the retention of the acquired firm's HVHR. We tested the model using data from a sample of 57 domestic, related, friendly Spanish mergers and acquisitions belonging to a wide variety of industries. The results support the notion that the more embedded the knowledge, the greater the impact of the acquired firm's HVHR retention on the knowledge transfer. They also show that the autonomy granted to the acquired firm, the frequency of use of rich media among the personnel of both firms, and the acquired firm's pre-acquisition profitability are factors encouraging the acquired firm's HVHR to remain. The study contributes to the literature on knowledge transfer in mergers and acquisitions by highlighting the relevance of retention of the acquired firm's HVHR for knowledge transfer, as well as demonstrating the importance of taking into consideration the nature of the knowledge to be transferred. It also contributes to the literature on the implementation process in mergers and acquisitions by identifying factors available to managers to favor HVHR continuity in the acquiring firm or the one resulting from the merger.