“Basil” the king of herbs is a rich resource of biochemicals ranging from polyphenols to essential oils having medicinal properties. Rosmarinic acid, a well-known polyphenolic compound is a caffeic acid ester derivative. It shows antioxidant, antiviral, antibacterial, anti-inflammatory and anti-proliferative like biological properties. Basil shows high morphological and biochemical variation thus raising the need to identify the potential cultivars for breeding and crop improvement studies. The present study reports collection of 15 sweet basil cultivars from six different countries and their analysis for studying variation in morphology both qualitatively [leaf shape, leaf margin, leaf color, stem color and flower color] quantitatively [days to flowering, plant height, branch number, inflorescence length and plant weight] and rosmarinic acid content in leaf, flower and roots separately. This study reports for the first time analysis of roots for rosmarinic acid content. HPLC results showed the leaf to contain higher amount of rosmarinic acid than flower and root. In leaves and flower highest rosmarinic acid was found in “Holy green” cultivar from Australia while in roots it was found in “Subja” cultivar from India. A correlation between geographical location and rosmarinic acid content was also found.