Due to the importance of Fusarium oxysporum, F. vasinfectum (Atk.) Snyder & Hansen in the State of São Paulo, improved strains, obtained by the cotton breeders of the "Instituto Agronômico", are often discarded because they are susceptible to Fusarium. This was the case of IAC 67/59. Wilt resistance was transfered to this line from 'IAC 17' by five backcrosses, without passing through selfed generations. The selection of the.