The studies on the gas-liquid mixing in an agitated vessel have been conducted by several investigators but have rarely been investigated for the mixing time of liquid in the laminar flow region. In this work, we tried to measure the mixing times and power consumptions in an aerated vessel agitated by a dual Rushton turbine, dual pitched paddle and single Maxblend at relatively low Reynolds numbers, where the isolated mixing regions were formed for dual impeller systems and poorly mixed regions for the Maxblend without gas dispersion. As a result, it was found that the mixing time was decreased drastically by the introduction of gas into the vessel for all impeller systems covered in this work, where the Maxblend shows the shortest mixing time and the smallest decrease in gassed power.