Many lichen specimens were collected from seven agroclimatic zones of Nilgiri Biosphere Reserve namely Udhagamandalam, Kotagiri, Kundah, Coonoor, Gudalur, Pandalur and Doddabetta. The study resulted in a total of 38 lichen species belonged to 17 genera within 10 lichen families. The family Parmeliaceae was dominant with maximum record of 56.7% of total lichens. The majority of lichen diversity was recorded at an altitude of 979 m with the total representation of 21.6%. Among the substrates corticolous lichen was found to be abundant with 81% followed by saxicolous (8.1%) and terricolous (5.4%). The majority of lichen belonged to foliose growth form which accounted for 45.9%. A species of fruticose lichen Ramalina obtusata (Arnold) Bitter, identified at an altitude of 2,197 m is a new addition to Tamil Nadu.