The exploatation od agro-industrial wastes as a source of bioactive ingredients, is gaining a significant importance in reecnt years, because ot its rich chemical composition and large available quantity. Onion peel and pea pod make a significant part of waste generated during produsctin and primary processing of onions and peas. In the effort to make the most of these secondary plant waste materials by means of bioactive compounds isolation, the aim of this study was to determine the influence of different extraction and hydrolysis conditions on the extraction of quercetin. Three conventional extraction methods (maceration, infusion and decoction) and two innovative techniques (ultrasound and microwaves) were evaluated. Extraction by decocteion resulted with the highest content of total polyphenols from both samples. Innovative techniques as well have shown a high extraction efficiency. HPLC analysis was used to qualitatively and quantitatively determine the polyphenolic composition of onion peel (protocatechuic acid, quercetin-3,4'-diglucoside, quercetin-3-glucoside, quercetin-4'-glucoside, quercetin) and the partial composition of pea pods upon hydrolysis (p-coumaric acid, synapic acid, quercetin). Using the combined extraction and hydrolysis at optimised conditions, protocatechuic acid (4.25 mg g-1) and quercetin aglycone (9.86 mg g-1) were extracted from onion peel. In pea pod, quercetin aglycone is present in significantly smaller amount, exclusivelly in conjugated form. Onion peel can be considered an excellent source of quercetin, while pea pod a relatively good source of quercetin, although further research in necessary to fully determine the polyphenolic composition of the pea pod.