Phenolic profile of 36 Cydonia oblonga Miller leaf samples, from 3 different geographical origins of Portugal, harvested in 3 collection months, was determined by HPLC/DAD. Quince leaf presented a common profile composed by 9 constituents: 3-0-, 4-0- and 5-0-caffeoylquinic acids, 3,5-0-dicaffeoylquinic acid, quercetin-3-0 galactoside, quercetin-3-0-rutinoside, kaempferol-3-0-glycoside, kaempferol-3-0-g1ucoside and kaempferol-3-0-rutinoside. C. oblonga leaf total content varied from 4.9 to 16.5 g/kg of dry matter, indicating that this leaf can be used as a good and cheap source of bioactive constituents. 5-0-caffeoylquinic acid was the major phenolic compound (36.2%). Significantly differences were found in 3-0-caffeoylquinic and 3,5-0-dicaffeoylquinic acids contents, according to geographical provenience and harvesting month.