Patrolling forest guards heard gun shots last night and found the rhino and her two year old calf with their horns removed near Hazarbigha camp in the southwestern area, park officials said today.
Four empty cartridges were recovered from the area.
A massive combing operation has been launched in the park and its adjoining areas to nab the poachers.
Of the 41 rhinos killed this year, Kaziranga National Park recorded 34 killings, followed by three in Orang and two each in Manas National Park and Pobitora Wildlife Sanctuary.
Rhino horn is highly valued across the world for its alleged aphrodisiac qualities and use in traditional medicine.