A study of the atmospheric pollen content was carried out on two series of samples collected respectively in 1973 and 1972 from the South of the Ivory Coast and from Chad respectively. The analysis revealed relatively important differences between the two regions, the first of which was in the Guinean zone and the second in the Sahelian zone. In the Guinean zone, the atmospheric pollen content, in spite of the dense vegetation, is weak and the pollen transport is negligible. In the Sahelian zone, where vegetation is sparser, the number of pollen grains in the atmosphere is more significant. In addition there is also a non-negligible number of allochtonous pollen grains brought by the wind coming from the north. The pollen grains of herbaceous plants are clearly dominant. A comparison of the results obtained at the two sites shows that rain and the degree of moisture in the air play an important part in the yield of pollen flow.