Amaranthus spinosus (Fam. Amaranthaceae) is an important aeroallergen in India and grows commonly in different parts of the country. In spite of its clinical significance in Type I hypersensitivity disorders, the antigenic and the allergenic properties of the pollen have not been systematically resolved. We investigated antigenic and allergenic properties of 5 pollen samples of Amaranthus spinosus collected from the Delhi area at fortnightly intervals. The protein content did not exhibit statistically significant variability. However, samples collected during the peak flowering season showed higher protein content. Biochemical characterization of samples showed multiple protein fractions by IEF and SDS-PAGE analysis. Samples collected during peak season showed a slightly higher number of bands (22) in the mw range of 14-70 kD. Seven protein fractions of 70, 66, 60, 50, 40, 30 and 14 kD were observed to have IgE binding capabilities and 9 were treated as allergenic. The observations will be helpful in standardizing pollen antigens for diagnosis and immunotherapy in India.