The reduction of gas streams containing sulfur dioxide to elemental sulfur is carried out by contacting a reducing gas, such as natural gas, methanol or a mixture of hydrogen and carbon monoxide, with recycled sulfur to produce a stream containing hydrogen sulfide that may be reacted with the gas stream that contains sulfur dioxide. Gas streams with a molar concentration of sulfur dioxide from 1 to 100% may be processed to achieve nearly 100% sulfur recovery efficiency.