Safety in the operating room (OR) has always been a major public health concern. It refers to the safety of both the patient and the working personnel. Improving patient safety is an increasing priority for surgeons and hospitals as sentinel events can be catastrophic for patients, caregivers, and institutions. Although patient safety in the operating room (OR) has improved in last decades, significant risks remain. Adverse events may be subtle and delayed (as a central line-associated bloodstream infection due to poor hand hygiene) or dramatic and immediate (e.g., a fire). All operating room personnel must have certain knowledge and skills to provide safety and quality care to patients before, during and after surgery. Review focused on the science of safety principles and efforts to improve safety in the OR.