Ambulatory surgery currently represents more than two thirds of surgeries performed. It is considered low-risk surgery and patients expect to be discharged home safely and comfortably the same day. More than 30 years of evidence supports the idea that preoperative assessment is best done by a focused history and physical, and only minimal, selective, further laboratory investigations. Costs are optimized by this approach and outcomes have not been shown to be adversely affected, possibly even improved, with less harm inflicted by additional testing. This article focuses on what is appropriate testing for ambulatory surgery patients.