This paper describes the first full scale field test of a steam injection system for a natural gas fired G.E. LM5000 gas generator for the purpose of: (A) decreased exhaust emissions, (B) increased power output, and (C) improved efficiency. It discusses the steam supply system, engine features, test results and plant economics for steam injection into the combustor and compressor discharge sections of the LM5000 at rates up to 65,000 LB/HR (29,510 KG/HR).