Every year, around 234 million surgical operations are performed worldwide ( Weiser, TG 2008 ), which are inevitably accompanied by mistakes. According to the US Institute of Medicine's report, Err is human – building a safer Health System, between 44,000 and 98,000 hospital patients die each year from a potentially preventable medical error ( Kohn LT 2000 ). Based on recently published data, the average postoperative hospital mortality in 28 European countries is 4.0%, in the Estonian cohort this figure was 1.5% ( Pearse, RM 2012 ). The incidence of postoperative complications depends significantly on the definition of complications and the accuracy of documentation, but according to various studies it ranges from 3 to 17% ( Gawande, AA 1992, Kable, AK 2002). Experts say that about 50% of reported complications are preventable ( Gawande, AA 1992 , Kable, AK 2002). Approximately 100,000 surgical operations or procedures are performed in Estonia every year, in which anesthesia is used. There are no data on the incidence of preventable complications. However, there is no reason to believe that the number of surgical complications in Estonia differs to a large extent from what is presented in the literature. The introduction of safety checklists started with the analysis of the causes of aviation disasters. Namely, it was found that 80% of disasters were caused by a combination of fatigue, stress, poor communication and preventable mistakes ( Ross, P. 2004). The introduction of safety control cards significantly reduced the number of air accidents despite a significant increase in air transport volumes. The World Health Organization (WHO) has developed a surgical safety checklist , which consists of three parts . Each part is performed at a specific time - the first part before the induction (starting) of anesthesia, the second part before the skin incision and the third part before the patient leaves the operating room. The introduction of the surgical safety checklist has greatly reduced both perioperative mortality and complication rates in both developed and developing countries. Mortality has been reduced by up to 50% and the incidence of complications by up to 35% ( Haynes 2009 ). The introduction of the control card has improved compliance with the requirements of perioperative antibiotic prophylaxis and thereby reduced the frequency of wound infections ( Thomassen, O. 2014 ). As a result of repeatedly checking the identity of the patient and the planned operation, the possibility of operating on the wrong patient or performing the wrong operation is reduced. Communication between the operating surgeon and other members of the surgical team has significantly improved, and awareness of the patient's health problems has increased ( Thomassen, O. 2014 ). The European Society of Anaesthesiologists (ESA) adopted a patient safety declaration in Helsinki in 2010, recommending the use of a surgical safety checklist as one of the safety measures (Mellin-Olsen, J. 2010 ). There was no experience of using such a safety data sheet in Estonian hospitals until 2013, which necessitated the preparation of this treatment manual. The goal of the treatment guide is to improve teamwork in the operating room and reduce the incidence of perioperative deaths, complications and errors.