Preventing surgical instruments from being retained in the patient after surgery has traditionally relied on nurses manually counting instruments used during the procedure. However, this method is not foolproof, and this qualitative study used interviews with operating room personnel to explore reasons for incorrect instrument counts. Not surprisingly, the issues identified are known contributors to safety issues in the operating room, including production pressures, poor communication between physicians and nurses, and overt disruptive behavior. In light of these findings, the authors argue that addressing the persistent problem of retained surgical instruments will require an improvement approach based on safety culture principles.