A three-level Boost DC-DC converter is proposed in this paper. Quasi Z-source converter acts as an auxiliary circuit to create soft switching condition for all active elements. Consequently. The converter efficiency is very high. Using a three-level structure in the proposed converter causes the maximum voltage stress across the semiconductor devices is limited to half of the output voltage. The converter has a high voltage gain and a small number of elements. The converter is analyzed with details in all operating modes. Furthermore, the experimental results are obtained to prove the converter performance based on the theoretical considerations.