Merck KGaA is a German chemical and pharmaceutical company. Merck, also known as “German Merck” and “Merck Darmstadt”, was founded in Darmstadt, Germany, in 1668, making it the world's oldest operating chemical and pharmaceutical company.

In September 2006 the company announced a takeover bid of $13.2 billion for Serono SA, Switzerland's largest biotech firm. The deal included a buy-out of the Bertarelli family's 64.5% stake in Serono to be followed by a public tender offer for the remaining shares starting in November 2006. The combined company has an R&D budget of approximately $1.1 billion and sales of approximately $4.6 billion. Its approximately $2 billion in sales of biologics would make it 7th among pharmaceutical/biotech companies. The new entity, Merck Serono, began operations in 2007.

As of July 2014, it had TH-302 at Phase III for soft tissue sarcome and pancreatic cancer, tecemotide for non-small cell lung cancer, and Pergoveris for poor ovarian responders.