Completion pneumonectomy (CP) is the complete removal of lung tissue remaining after an initial ipsilateral partial pulmonary resection and is one of the most invasive operations in the field of general thoracic surgery. Mortality and morbidity rates are higher after CP than standard pneumonectomy. CP is a highly demanding procedure, usually due to major pleural and sometimes pericardial dense adhesions from previous surgery or infection. Intra-pericardial control of the pulmonary artery and veins is recommended to avoid vessel injury. Therefore, this operative intervention should be performed only by experienced thoracic surgeons on carefully selected patients in order to improve postoperative outcomes. Preoperative pulmonary and cardiac functions are decreased by the previous procedure. In addition, the rate of complications is high because of excessive operative invasiveness. Therefore, preoperative assessment, surgical indication, low invasive surgical technique, and good postoperative management are very important elements when CP is performed. On the other hands, CP may be a reasonable option for postoperative lung cancer recurrence or new primaries only in carefully selected patients, in whom the potential oncological benefits overweigh the surgical risk. This article reviews these operative knack and pitfalls.