The authors studied the selection of nine tomato varieties, 10 progenies and plants of L. pimpinelilfolium specie (P.I. 126915-1-8) to one new isolate of F. oxysporum f. lycopersici (Wr) Sny & Hans, under controled green-house condition. The selection observed during the experiment were the following: 1 - The commercial varieties with resistance to races 1 and 2 of F. oxysporum f. lycopersici were susceptible to the new isolate of the fungus. 2 - The plants of L. pimpinellifolium were resistant to the isolate test. 3 - The authors suggest that the isolate of the fungus studied be regarded as race 3 of F. oxysporum f. lycopersici (Wr) sny & Hansen.