Grape skins are a potential source of phenolics that can be used in the food, cosmetic and pharmaceutical industries. The phenolic composition of grape pomace skin, a by-product of winemaking, was investigated. The air-dried pomace skin of four grape cultivars, Carignan, Merlot, Cabernet Sauvignon, and Syrah, was studied. Carignan skin had the highest concentrations of caftaric acid (11.96 ± 3.99 mg/g DW), rutin (9.23 ± 1.15 mg/g DW), quercetin 3-glucoside (97.76 ± 10.00 mg/g DW), kaempferol 3-glucoside (82.23 ± 33.22 mg/g DW) and resveratrol (4.83 ± 2.02 mg/g DW). Syrah skin had the highest concentration of gallic acid (36.33 ± 1.75 mg/g DW) while Cabernet Sauvignon skin had the highest concentration of catechin (12.83 ± 2.20 mg/g DW).