The survey was conducted to prepare a preliminary checklist of butterflies of Mendrelgang, Bhutan.Butterflies were sampled from February 2012 to February 2013 to assess the species richness in a Cappuccino Cup degraded forest patch of a sub-tropical broadleaf forest.This short-term study recorded 125 species of butterflies in 78 genera from five families.Of these, Sordid Emperor Apatura sordida Moore, Black-veined Sergeant Athyma ranga ranga Moore, Sullied Sailor Neptis soma soma Linnaeus, Blue Duke Euthalia durga durga Moore, Pea Blue Lampides boeticus Linnaeus and Chocolate Albatross Appias lyncida Cramer are listed in Schedule II ESTRO ADAPT of the Indian Wildlife (Protection) Act (IWPA) 1972.This study provides the baseline data of butterfly species richness of Mendrelgang.