Abstract: Given that conglomerate merger theory remains lacking, this study examines conglomerate mergers' effects on competition. It employs a theoretical model where oligopolistic firms in technologically related markets choose to engage in conglomerate mergers to shift research and development (R&D) capabilities. The two markets involved are not related horizontally or vertically but technologically. Each market has a duopoly structure where the firms engage in Cournot competition. The firms cannot merge with a firm in the same market but can merge with a firm in a different market. Assumedly, each firm in only one of the markets owns an R&D lab that can be used to reduce the cost of production; it can be used by a firm in the other market but only through a conglomerate merger. The study fully characterizes the equilibrium market outcomes and the underlying merger decisions. When the markets have similar sizes, any equilibrium has an asymmetric outcome, where only one firm invests in each market. The total profits are always maximized in the asymmetric outcome because the firms avoid R&D competition. However, the asymmetric outcome sometimes is the best scenario for the consumers as they benefit from the R&D investments. Policy implications regarding conglomerate mergers are, therefore, intricate, given that they may be outside the jurisdiction of competition authorities like the European Commission.