Technical Abstract: Members of the Allium genus are consumed for their culinary flavor attributes, but also contain antioxidant and anticarcinogenic phytochemicals. Welsh onions (Allium fistulosum L.) are commonly used in Asian cuisine, where both leaves and pseudostems are consumed. Carotenoids are an important class of phytochemical gaining attention for their health attributes. The goal of our study was to characterize carotenoids and chlorophylls present in leaf tissues, and to indentify genetic and environmental differences in carotenoid concentrations among A. fistulosum accessions. Twelve USDA-ARS accessions were field grown in Knoxville, Tenn. and Geneva, N.Y. during the summer of 2007. After harvest, carotenoid and chlorophyll pigments were evaluated in leaf and pseudostem tissues using HPLC methodology. We were able to identify the presence of antheraxanthin, ß-carotene, lutein, neoxanthin, and violaxanthin in leaf tissues; however, pigments were not found in pseudostem tissues. Carotenoid and chlorophyll concentrations did not differ between locations or among accessions. It is possible that accessions evaluated in this study are genetically closely related, or were selected based on flavor attributes and not leaf tissues pigmentations.