As practitioners in the U.S. and Europe alike adapt business concepts and techniques for use in a nonprofit or social enterprise context, we need to know more about the organizational challenges of implementing specific techniques such as social return on investment (SROI) measurements and about variations across cultural contexts. This paper identifies and describes several state-of-the-art approaches to valuing SROI, reviews the organizational challenges and innovative approaches to implementing an SROI measurement process, and examines and compares in detail organizations two in the U.S., two in Europe that have attempted to use SROI valuation methods. Implications for both scholars and social investment/social enterprise practitioners are drawn