Evans and Kauffman were the first to identify, isolate and successfully culture embryonic stem cells using mouse blastocysts. This discovery opened the doors to the creation of “murine genetic models” -- mice that have had one or several of their genes deleted or otherwise modified to study their function in disease.

In 2007 Evans shared the Nobel Prize in Physiology or Medicine with Mario R. Capecchi and Oliver Smithies "for their discoveries of principles for introducing specific gene modifications in mice by the use of embryonic stem cells."