United Surgical Partners International (USPI) is an American ambulatory care company based in Dallas, Texas. It was founded by Don Steen in 1998. USPI currently is active in 28 states. USPI currently operates over 400 ambulatory facilities serving 9,000 physicians and 3.4 million patients annually. The company had partnerships with over 4,000 physicians and over 50 health systems in the United States, with over 19,000 employees. The company went public in 2001 and was taken private again in 2007.