The effects of cowpea (Vignaunguiculata) and groundnut (Arachis hypogea) on succeeding sorghum yields, soil mineral N and nematode infestation were studied during five cropping seasons (2000 to 2004) in a weakly acid Ultisol of the agronomy research station of Farakô-Balocated in the Guinean zone of Burkina Faso, West Africa. A factorial 5 × 5 design of five crop rotations with five fertilizer treatments in a split-plot arrangement with four replications was used. Sorghum yields were affected by the two factors (rotation with legumes and fertilizer applications) during the four years. But interactions were not observed between the two factors. Monocropping of sorghum produced the lowest yields and legume-sorghum rotations increased sorghum yields by 50% to 300%. Groundnut-sorghum and cowpea-sorghum rotations increased soil mineral N by 36% and 52%, respectively. Crop rotation influenced nematode infestation but the effects on soil and sorghum root infestation differed according to the rotation. The cowpeasorghum rotation increased soil and sorghum root infestationby nematodes while groundnut-sorghum decreesed the nematode population. The soil of the cowpea-sorghum rotation contained 1.5 to 2 times more nematodes than the soil of the monocropping of sorghum. In contrast, the soil of the groundnut-sorghum rotation contained from 17 to 19 times fewer nematodes than that of themonocropping of sorghum. However, nematode infestation did not affect any of the succeeding sorghum yields. It was concluded that the parasitic effect of nematodes was limited by the predominance of positive N-effects on the development of succeeding sorghum.