This study showed the first had information on 57 interesting medicinal herbal plants used by tribal people, Vaidyas, Siddha and Ayurveda for diabetes mellitus. Present enumeration of antidiabetic herbal flora of Tamil Nadu includes information regarding previous findings. This informations were gathered at the time of field study from various local inhabitants, viz., vaidyas. Medicinal plant seller, healers, priests, hakims and local elderly people. Furthermore, informations regarding antidiabetic nature of plants were confirmed by previous findings reported in various national and international journals.