Implant therapy is a safe and increasingly common way of dealing with partial or complete loss of teeth, however, it is not entirely without risk. The reason for this lies in the fact that implants are often not placed into the bone, which is ideal with regard to its quality and quantity, therefore the knowledge of possible complications is of great importance for every implantologist. Complications can occur at any stage of the implant therapy and are usually classified according to the time of their occurence. We can distinguish intraoperative complications which arise during the operation and include bleeding caused by vascular injury, damage to the mandibular nerve, mandible fractures, damage to the adjacent teeth, lack of primary implant stability, perforation of the maxillary sinus and migration of implants into the sinus. Their resolution must be immediate because some of them pose a potential threat to the patient's life. Postoperative complications occur at different time periods, earlier or later after surgery. These are edema, early postoperative bleeding, ecchymosis and hematoma, emphysema, soft tissue dehiscence, implant fractures, development of infection at the site of implantation and the occurrence neurosensory impairment, mucoperiosteal flap perforation, maxillary sinusitis, loss of osseointegration and periimplantitis. Periimplantitis is most common complication and may also occur years after implantation. Therefore, regular examinations and X-ray diagnostics are necessary in maintenance stages of placed implants. However, the biggest complication in implant therapy is dissatisfied patient. Therefore, proper pre-operative preparation and planning reduce the risk of complications to a minimum and provide what patients at the beginning of the therapy expect.