Conventional four-switch buck-boost converter (FBBC) has been widely used for battery-powered portable devices when a voltage between the min and max voltages of the battery is needed. However, its power efficiency is limited because of high conduction and switching losses. In this paper, a power-efficient hybrid buck-boost converter (HBUBOC) is presented. The proposed HBUBOC reduces RON and DRC conduction loss, and switching loss simultaneously, thus, achieving high efficiency in both the buck and boost modes, over a wide range of conversion. The proposed HBUBOC achieved a max/min efficiency up to 97/85.43 % over a load current of 0.1-1 A and input voltage of 2.5-5.5 V at 3.3 V output voltage. This performance can be considered as the highest over both buck and boost modes compared to the most recent reported state-of-the-art counterparts if same switches and low-profile high-DCR inductor are used.