A single stage process for treating pyrolysis gasoline containing acetylene, diolefins, sulfur compounds and nitrogen compounds to react a sufficient amount of said acetylene and diolefins with hydrogen to produce saturated products and hydrogen sulfide to provide a pyrolysis gasoline product suitably for use as gasoline blending stock comprising: feeding pyrolysis gasoline and hydrogen at a mol ratio of hydrogen to pyrolysis gasoline of at least 0.5:1 and preferably in the range of 1:1 to 3:1 to a hydrodesulfurization zone containing a hydrodesulfurization catalyst such as cobalt/molybdenum under vapor phase conditions at a pressure in the range of 200 to 500 psig at a temperature in the range of 550° F. to 850° F. The operating temperature is at least above the dew point of the mixture of pyrolysis gasoline and hydrogen, preferably in a range 50 to 400° F. above said dew point.