The present study was conducted to determine flavonoid contents in aerial parts of Adiantum capillus- venerisL. (Pteridaceae) collected from two different sites: Gali Ali Bek in Erbil district and Kalar in Sulaimaniyah district, in Iraqi Kurdistan-Northern Iraq by using HPLC technique. Six flavonoid compounds: Kaempferol, Kaempferol-3-O-glycoside, Luteolin, myricetin, quercetin and rutin were identified in A.capillus-veneris growing at both sites. These compounds showed differences in their concentrations at each site and between sites. It was concluded that flavonoid content of this fern was interrelated with site attributes.