This paper addresses the following two questions: (i) Is there any evidence that firms, like human beings, prefer to partner with alike? (ii) Is there any relationship between the ex ante technological and product relatedness of merging parties and the postmerger performances? Using data of patent holdings and product portfolios of big pharmaceutical companies, I find that (i) merger deals are more likely to be signed between firms with related technologies and drug portfolios, and (ii) product relatedness and technology relatedness are positively and negatively correlated with postmerger performances, respectively. The analysis suggests that the negative effect of technology relatedness might be driven by a large human capital depreciation following consolidations. The results have important implications for competition policy, which are discussed in the concluding section.