Unintentional missing of shrimp and soybean allergen information on precautionary food allergen labeling often occurs in sauce products. To avoid food allergies, sensitive and time-saving analytical methods are urgently needed. However, the currently reported methods usually employed labeled peptides for isotope internal standard quantitation, and the matrix effect caused by protein extraction or digestion can not be corrected. In this study, a labeled peptide-free standard addition method was developed for simultaneous determination of shrimp and soybean in sauce products using ultrahigh-performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS). Through the rational selection of stable peptides, satisfying mean recoveries and relative standard deviations of the chosen peptides are achieved. The limit of quantifications of each peptide ranged from 0.25 to 5 mu g tropomyosin/g sauce and from 1 to 10 mu g Gly m 6/g sauce, respectively. Using the labeled peptide-free UHPLC-MS/MS method, not only ideal experimental results were obtained surpassing those obtained with labeled peptides, but also the reagents were economized and shortening of the sample preparation time was achieved.