Results are reported on the application of the soil fumigants "D-D" (dichloropropene-dichloropropane) and "Dowfume W-40" (ethylene dibromide) for the control of the root-knot nematode on potatoes. The experiments were done at Campinas (State of São Paulo, Brazil) in soil of the "Glacial" type. The tests cover two distinct phases. In the first the soil of certain plots was fumigated 18 days prior to planting. There were four treatments : fumigation and fertilizer, fumigation without fertilizer, fertilizer alone, and without fumigation or fertilizer. In the second phase, performed a year later on the same land, no fertilizer was used and no fumigant applied in order to determine the residual effect of the chemicals. In the second phase two potato varieties were used instead of only one as in the first. The results show that : a) Neither "D-D" nor "Dowfume W-40" harmed the production of tubers. b) In the first phase of the experiment the production of the plots with fumigants and fertilizers was slightly better than that of the plots with fertilizer only and in turn the latter was better than that of the plots without fumigants and without fertilizer. In the second phase there was almost no difference between plots with chemical treatments and plots with fertilizer. c) "D-D" as well as "Dowfume W-40" efficiently reduced root-knot nematodes on the tubers. This is shown in the 1st phase of the experiment by the plots without fumigation and without fertilizer, where 49.5% of the tubers were galled, mostly seriously ; on the plots that received only fertilizer, 20% were galled while those fertilized and fumigated with "D-D" were 1.5% galled and with "Dowfume W-40" 0% In the 2nd planting on the same site the residual fertilizer however did not reduce the formation of galls. Further experiments are planned.