Background: Peach is a common food allergen source throughout Europe. The aim of this study was to characterize peach allergy in a Portuguese patient population. Methods: Thirty peach-allergic patients confirmed by double-blind placebo-controlled food challenges and 29 controls were included. All subjects completed a standardized questionnaire regarding symptoms and epidemiologic characteristics, skin prick tests with inhalant allergens and foods as well as specific IgE antibodies to peach, recombinant peach allergens rPru p 1, rPru p 3, rPru p 4 and cross-reactive carbohydrate determinants. Results: Thirty-seven percent of patients reported only oral allergy syndrome, while 37% reported generalized urticaria and/or angioedema, 17% localized contact urticaria and 10% anaphylaxis with peach. Sensitization to other Rosaceae fruits and tree nuts was present in 90 and 77% of the patients, respectively. Respiratory allergy history was associated with less severe symptoms (oral allergy syndrome or contact urticaria; p < 0.01) and positive skin prick test to peach peel or plum with more severe symptoms (urticaria and/or angioedema or anaphylaxis; p < 0.05). Ninety-seven percent were sensitized to Pru p 3, 13% to Pru p 4, 3% to Pru p 1 and 10% to cross-reactive carbohydrate determinants. Pru p 3 specific IgE was associated with Artemisia vulgaris sensitization and tree nut allergy (p < 0.05) but not with clinical severity. Conclusions: Half the patients reported systemic reactions to peach. Peach allergy appeared predominantly mediated by Pru p 3 but some patients were sensitized to Pru p 4. Applying a 0.10 kU_A/l cutoff level, the diagnostic value of combining the 3 recombinant allergens was noteworthy, with 100% sensitivity and 90% specificity.