The combined method of estimation labor cost based on the analysis of literature on the topic of labor cost estimation, including modern approaches and those that were used before the intensification of IT technology development to support the life cycle of the project, a combined method of estimation was developed. Labor cost estimation in the development of complex technical devices is an important project management tool. Various estimation methods provide accurate and objective data necessary for resource planning and budget control. The proposed method takes into account the factors affecting labor costs, which provides an increase in the efficiency of the development of complex technical devices. The paper presents the results of a numerical experiment of labor cost estimation. An important role in the evaluation is played by the availability of qualified and experienced staff of specialists, as well as possible professional development during the project implementation period.