Whey protein hydrolysates (WPH) are known for bioactivity and functionality, but WPH also have a distinct bitter taste. Identification of effective bitter taste inhibiting agents for WPH would broaden the use of this ingredient. The objective of this study was to evaluate the effectiveness of 24 documented bitter taste inhibitors for WPH. Two spray-dried WPH with different levels of hydrolysis (DH) were evaluated with each potential inhibitor. Quinine hydrochloride (quinine) was presented as a control with each WPH. Percent bitter taste inhibition was reported relative to quinine bitterness. Effective bitter taste inhibitors were subsequently evaluated in WPH beverages with vanilla and chocolate flavoring followed by descriptive analysis. The compounds evaluated did not inhibit bitter taste of quinine and the 2 WPH in a similar manner (P < 0.05). Effective bitter taste inhibitors (P < 0.05) of both WPH were sucralose, fructose, sucrose, adenosine 5' monophosphate (5'AMP), adenosine 5'monophosphate disodium (5'AMP Na(2) ), sodium acetate, monosodium glutamate, and sodium gluconate. Sodium chloride inhibited bitter taste of WPH with high DH but not WPH with low DH. Amino acids (l-Lysine, l-arginine) inhibited bitter taste of quinine but not WPH. All effective inhibitors in rehydrated WPH were also effective in the beverage applications. Sweeteners (fructose, sucralose, and sucrose) enhanced vanilla and chocolate flavors in beverages. Most salts and a nucleotide, while effective for bitter taste inhibition, suppressed vanilla and chocolate flavors and potentiated other flavors (that is, sour aromatic), and basic tastes (salty, sour). CONCLUSIONS The bitter taste of whey protein hydrolysates (WPH) limits their use as ingredients. This study identified effective bitter taste inhibitors of WPH with different peptide composition and provides insights for effective bitter inhibitors for product applications with WPH.