Proteomics (proteome analysis) has been utilized to investigate the molecular mechanisms underlying the beneficial effects of food factors on human health. Food factors such as polyphenols affect the expression profile of proteins globally and induce post-translational modifications of amino acid residues, including phosphorylation and oxidation. Proteomics enables researchers to analyze the effects of food factors on cellular events and the mechanisms involved in a comprehensive manner. The proteomic analyses are carried out using separation techniques such as electrophoresis and chromatography, along with detection methods that rely on antibodies, fluorescent dyes, or mass spectrometry. This chapter describes current proteomic technologies that are useful for elucidating the physiological functions of food factors.