WHO classification for therapeutic purpose under field condition: 1. Paucibacillary–with bacterial index less than 2+, 2. Multibacillary–with bacterial index 2+ or more. National leprosy control programme: 1. Non-lepromatous (N) (a) Tuberculoid (T), (b) Maculoanaesthetic (MA), (c) Polyneuritic (P). 2. Non-lepromatous (N) (a) Tuberculoid (T), (b) Maculoanaesthetic (MA), (c) Polyneuritic (P). 2. Intermediate (NXNL): (a) Borderline (B), (b) Indeterminate (1). 3. Lepromatous (L). Ridley jopling classification (Based on clinical, bacterial, immunological and histopathological basis).