Abstract: A chimney reinforcement device to be secured to a damaged or sound chimney comprising two front corner brackets and two rear corner brackets, which are bolted together to reinforce the upper portion of the chimney. Two wall mounting members are connected between the front corner brackets and the building so as to allow the front corner brackets to be firmly anchored to the building structural materials adjacent the chimney just below the roof line. The chimney reinforcement device further comprises two inclined arm member connected between the rear corner brackets and the roof such that the corner brackets are firmly anchored to the roof structure adjacent to the chimney. When the chimney reinforcement device is properly secured to a chimney, the chimney reinforcement device adds strength to the existing framework of the chimney and thereby prevents severe cracking or falling thereof during an earthquake.