The recently published genome of peanut enables detailed molecular description of seed storage proteins, particularly allergens, which make up the peanut seed proteome. A detailed description of the allergenic proteome was produced using peanuts of different genetic backgrounds to increase the coverage of potentially expressed proteins and additionally allows for analysis of protein variability. Using relative quantification by mass spectrometry, minor variation of some allergenic proteins was observed but total levels of Ara h 1, 2, 3 and 6 were relatively consistent among genotypes. The isoform compositions of Ara h 1, 2 and 6 were similar. Three Ara h 3 isoforms were variable among genotypes and contributed to a large proportion of total Ara h 3 when present. The immunologically relevant amino acid modification hydroxyproline, previously thought to be present only on Ara h 2, was detected on Ara h 1 and 3 in consistent proportions given when the associated isoforms were present. The relevance of the data was evaluated in terms of food allergy regarding applications to reference materials, diagnostic and immunotherapeutic use, detection of peanuts in food, and risk assessment. The data can be used to design targeted mass spectrometry methods to permit analytical control of such materials.