Background and Objective: Buckwheat is considered one of the most important food allergens in Korea. Although a very small amount is ingested or inhaled, it can cause seri- ous allergic reactions. However, the major allergens of buckwheat still remain to be eluci- dated. The aim of our study was to identify and characterize the major allergen of buck- wheat seed. Material and method: Dialysis membrane with a cut-off MW 1kD was used for the preparation of crude buckwheat seed allergen extract. SDS-PAGE under reducing condi- tions and IgE immunoblotting were performed using sera from 15 buckwheat sensitive sub- jects. Isoelectric focusing and lectin blotting assay were done. Result: Western blot analysis showed more than 15 IgE-reactive buckwheat proteins. Among them, a 24kD protein was shown to be the most frequently bound to sera from allergic subjects (54%). Isoelectric point of 24kD protein was around 5.9. In lectin blotting assay, 24kD protein did not bind to Con A nor five other lectins. Conclusion: A 24kD protein was the most frequently recognized allergenic component in buckwheat seed. Isoelectric point was around 5.9. Glycosylation was not detected in 24kD of buckwheat protein.