Parasitic flowering plants of the genus Striga cause extensive damage to cereal and legume crops in Africa, but factors affecting seed dispersal have not been well understood. Petrolatum-coated microscope slides placed at regular intervals from Striga hermonthica plants and suspended at 1-, 2-, and 3-m heights from trees within and around S. hermanthica-infested fields indicated that distribution of seeds by wind was not extensive. The maximum horizontal distance that seeds were caught was 12 m and the maximum vertical distance was 2 m. Samples of local market supplies of cowpea, maize, millet, and sorghum from six areas of Nigeria over 2 yr contained an average of 20.9, 32.4, 24.2, and 27.3 Striga seeds, respectively