A study was conducted to test the effectiveness of Curater 10 G (10% Carbofuran) on the parasitic nematodes associated with 5 cowpea varieties. Each variety was planted into two adjacent plots, one of which was treated with 400g a.i/ha of Curater 10 G and the other left untreated. Nematodes population densities in the field were assessed prior to nematicide application and planting, at mid-season and at crop maturity. At maturity, plants were harvested from both treated and untreated plots and the yields recorded. Yield loss and the percentage yield reduction were calculated. Initial population of the plant-parasitic nematodes was quite low. Although the population densities of these nematodes increased in the treated as well as untreated plots, the final population densities were higher in untreated than in treated plots. The yield gains were significant in four of the five varieties (IT 227-2 K- 90 , KD 89 IT -391 , IT 88 DM-345 and the local Foumbot). But in general, the yield increases on IITA varieties were not significantly different from that obtained on the local Foumbot. For these varieties yield grains ranged from about 28 to 68%. This shows the sensitivity of these cowpea varieties to parasitic nematodes and the bioefficacy of carbofuran.