In this paper, a 3-D Luneburg Lens is employed for direction finding application. Using the special property of a Luneburg lens that every point on the surface of the Lens is the focal point of a plane wave incident from the opposite side, a number of detectors are mounted around the surface of the lens to estimate the direction of arrival (DOA) of a microwave signal. To demonstrate the proposed direction finding system, a Luneburg lens with five detectors mounted on its surface to receive the signal from 20° to 20° is measured at 5.6 GHz. The initial direction finding results using a correlation algorithm show that the estimated error is smaller than 2° within 15° to 15° incident angles. © 2012 IEEE.