Oral communication. Argania spinosa (L.) Skeels (Sapotaceae) is an endemic tree located mainly in south-western of Morocco. The argan tree plays medicinal, ecological and socioeconomic roles in this area. The fruit of A. spinosa has oil-producing kernels with a high unsaturated fatty acid content. The argan oil is greatly used in food and cosmetic products. Kernel, pulp of fruit and trunk have also been studied for sterols, triterpenes and saponins. Our goal in this study is to investigate the leaves for phenolic compounds by HPLC in 90 specimens of argan tree from three localities in Souss Massa area (south-western Morocco). Quantification and histolocalisation of phenolic components, i. e. flavonoids and condensed tannins (molecules well known for their broad spectrum of biological activities) in the three localities were carried out using chromatographic and spectroscopic methods combined to histochemical technics. Flavonol glycosides were quantified by HPLC from argan leaves. The main flavonol glycoside was myricitrin. The content of myricetin derivatives was higher than the quercetin derivative content. With regard to chemotaxonomy, four flavonol glycosides seem to be good markers for this species as they were detected by HPLC in 90 specimens of argan tree from the 3 localities. The histochemical studies of the different parts of A. spinosa (leaves, stems and thorns) have shown a high concentration of myricetin derivatives in the peripheral tissues, this cell localisation of the flavonoids could explain the Argan tree adaptation to aridity