Most of cases in deformity surgery are complicated and demands long time period for treatment. Therefore, surgeon have to be meticulous in planning, surgery and follow-up phases. Although all the principles of the deformity surgery are precisely followed, it is possible to encounter various complications during the treatment process. The course of treatment generally is not effected and a minor intervention is sufficient. Some of complications effect the course of treatment and prolong the treatment. Some serious complications effect the outcome and change both result and duration of treatment. In this respect, it is possible to divide the complications into major and minor complications. It is an advantage for us to know which complications we may encounter at which stage of treatment. In this case, all complications can be classified into three groups as early and late complications. It is important to recognize the complications as well as how to treat them. Correct intervention in the right time is most important in the fight against complications. For this reason, it is crucial to inform patients and their relatives before surgery and to guarantee their cooperation. Being on alert and having ability to fight against complications are most powerful tools on the way of success. The risks of complication will decrease as well as our knowledge and experience in deformity surgery increase in time.