Abstract: Methods of preparing 2 forest fire extinguishing agents were described. The main ingredient of the first one, named as"704", is the common fertilizer, ammonium phosphate, while that of the second, named as "type 75", is a mixture of ammonium sulphate and phosphate. Effectiveness of those agents was tested by loading 1 ton of them in a Trans. -5 airtanker, flying at a height of 30-40m with a crusing speed of 150km./hr., and spraying in amount of 0.4-0.7 kg/m² wind velocity at ground level was 5-6m/sec. at the time. Surface fire, scrab fire, and grass fire, in woods of valley lowland were effectively retarded and put out.