Analysis of quality-related parameters at the green leaf-stage and in orthodox-made tea revealed marked quality deterioration with increasing blister blight severity. Total phenols, catechin(s), total nitrogen, amino acids, and chlorophylls, as well as polyphenol oxidase activity, declined in tea shoots with increasing disease severity. Depending on disease intensity, orthodox tea made from infected shoots showed loss in leaf-style. Likewise, theaflavins, thearubigins, caffeine, and high polymerized substances as well as total liquor colour, brightness and briskness also exhibited marked progressive decline in tea made from shoots with increasing disease severity. Aroma components, particularly hexene-1-ol, phenyl acetaldehyde, linalool, methyl salicylate, geraniol, indole, β-ionone, nerolidol, and several unassigned components were also lower in disease affected teas. The magnitude of decline in various aroma constituents corresponded to disease intensity.