Official sources said the leopard first attacked Mahen Saikia when he was going to a paddy field at Kamarbandha's Basa Bharalua Kanimahal Chariali.
Another person, Prafulla Saikia, then went in search of the animal and he was attacked by the leopard.
In defence, Prafulla Saikia also attacked the leopard with a machete which he was carrying with him.
The severely injured leopard died before medical help could be provided. Police and forest department officials reached the spot soon after.
Meanwhile, both the injured persons have been admitted to a local hospital.