The U.S. energy services company (ESCO) industry has long been recognized for its role in delivering energy efficiency and related energy services to customers with large and medium-sized facilities. Recently, utilities, their customers, and state, local, and federal governments have developed renewed interest in energy efficiency to address concerns about rising fuel and electricity prices, climate change, increasing cost estimates of building new baseload generation, and challenges in siting new power plants and major transmission facilities. This is reflected in a consensus of regulators, utilities, industry representatives and customer groups established through the National Action Plan for Energy Efficiency (NAPEE 2006). Utilities, and state and federal regulators and policymakers are beginning to ramp up activities designed to encourage and support increased energy-efficiency investment. To be effective, they will need to consider models for procuring energy efficiency in various markets. This study, based on a survey of 46 ESCO companies, provides information to policymakers and industry participants on ESCO market development, growth and capabilities.