Pharmaceutical markets are no exception to the increasing importance of data as key competitive input. This chapter provides an overview of competitive issues posed or potentially posed by business conduct related to the supply and manipulation of pharmaceutical data. It has been written prior to, and does therefore not refer to, the Bundeskartellamt investigation against Facebook regarding data, so if that matter could be of relevance, it is not dealt with in this chapter. A consideration of relevant market definition serves as starting point, where it is already apparent that there is one single company (and a name old-known to competition practitioners) that has quite an advanced position in the markets related to pharmaceutical marketing information (IMS Health). Typical company conduct around data potentially affecting competition is depicted, including some recent instances of monopolization or attempted monopolization cases. Finally, a few considerations on merger control are included in view of the relatively recent controversy around merger thresholds and the revision of thresholds in various jurisdictions. The last revision of the chapter took place in July 2018.