Complications are any deviation from the ideal postoperative course that is not inherent to the procedure, and does not involve a failure to heal. Complications occur after surgeries, therefore, surgeons must be skilled in predicting, recognizing, and treating of those. They range from seemingly minor incidents that resolve without any consequences, to serious incidents that can be life-threatening. There are numerous risk factors that influence the occurrence of complications (different diseases, bleeding, medications, etc.). In 1992, Clavien and colleagues proposed a standardized method for classifying surgical complications, known as the T92 system or the Clavien classification of surgical complications. Based on that, numerous other classification methods have been developed. Clavien and colleagues made significant modifications to the classification in 2004. Complications can also be classified according to organ systems, including general, cardiac, pulmonary, gastrointestinal, renal, urinary tract complications, hematological, neurological complications, as well as complications of the skin and soft tissues. Preventing complications is not easy; it requires teamwork and a systematic approach to achieve the highest quality of care that patients expect and deserve. After the surgery, the patient is transferred to the recovery room, where specially trained staff and equipment for early detection and treatment of these disorders are available. To successfully prevent and treat postoperative complications, once they occur, the joint efforts of both the surgeon and the patient are necessary.