Lupin seeds are high in protein and dietary fibre but low in fat and starch and a number of health benefits have been associated with their consumption. As a result of these positive characteristics lupin seed components are increasingly being used as foods and food ingredients. However, allergic reactions to lupin have been reported on ingestion or inhalation of lupin seed proteins. In this study we have characterised the proteins from Lupinus angustifolius (narrow-leafed lupin) seeds that are allergens and also analysed genes encoding major seed storage proteins. To identify the allergenic proteins, L. angustifolius seed proteins were separated by two dimensional (2D) gel electrophoresis. Western blots of these gels were screened with serum from individuals allergic to lupin and the proteins that bound IgE (allergens) were identified by mass spectrometry. IgE reactive spots were positively identified (had two or more peptide matches to the same protein) and 32 corresponded to conglutin β β β β, one of the major seed storage proteins. In the initial part of the study, sera from individuals allergic to lupin but not peanut was used to characterise allergenic proteins. There is evidence that some individuals who are allergic to peanuts are more likely to be allergic to lupin and it is possible that these people react to different allergens. We are now investigating which lupin proteins are allergens for these people who react to lupin and peanut and conducting challenge tests to determine the identity of the cross-reactive allergens.