Skin sensitivity reactions to a variety of antigens in 290 unselected urban Nigerian children suffering from bronchial asthma of varying severity, are reported. The percentages of positive skin reactions to the first four antigens were as follows: Ascaris (25%), Dermatophagoides pteronyssinus (21%), house dust (12%) and feathers (12%). The sizes of reaction were generally smaller than those reported in European and American children. While the relatively high sensitivity to Ascaris was probably fortuitous, further studies are needed to evaluate the actual role, if any, of the parasite in bronchial asthma affecting the African child. The relatively low rate of positive skin reactions indicate that, at present, skin sensitivity tests are of limited value in the identification of aetiological factors in asthma affecting Nigerian children. The development of local materials for skin testing may however enhance the usefulness of this investigation in future.