Flow and temperature fields were numerically analyzed in a bench-scale gas-injected molten steel bath. A cylindrical vessel containing molten steel was considered. A stream of argon was injected vertically upward through a nozzle located at the bottom center of the vessel. The problem was formulated on the basis of a two-fluid model using the Eulerian approach for both gas and liquid phase transports. Effects of gas flow rate on flow field and on intensity of mixing in the bath were investigated in isothermal systems. To study heat transfer mechanisms between the gas and melt, temperature field equations were solved for both phases in a nonisothermal system.