BACKGROUND Most of the humeral shaft fractures can be successfully treated conservatively. Due to increasing number of multiple and high-energy injuries, necessity of patient's compliance and restriction of his selfcare is conservative treatment in background. Humeral shaft fractures indicated to operation treatment are mostly solved by closed reposition and internal fixation with intramedullar nail (CRIF) or open reposition and internal fixation (ORIF). OBJECTIVE The aim is to prove that miniinvasive plate osteosynthesis (MIPO) of the humeral shaft fractures combines advantages of the both currently used methods. In other words, to use a plate osteosynthesis with minimal invasiveness and to exclude unexpected complications of radical operation approach by open reposition and problems related to nailing. METHODS From March 2007 to August 2008 we operated on 20 patients with humeral shaft fractures using MIPO technique. Fractures were classified according to AO-classification: A - 9x, B - 5x, C - 6x. There were monotraumas and multiple injuries, as well. RESULTS The results were evaluated by Constant-Murley test and Liverpool elbow scoring system. The mean value was 92/9.1 points. In 75% of patients we have reached good and excellent results. Complications were observed in 5 patients (20%). All patients have been healed. CONCLUSIONS In spite of the limited number of patients in case serie our results are in accordance with current published data. Minimally invasive plate osteosynthesis is in our opinion safe and effective operation method for humeral shaft fractures treatment.