We will discuss reults of the experimental and theoretical study of the low-frequency noise in GaN/AlGaN 2D structures and examine possible sources of noise, including contacts, surface and 2D channel itself. 2D GaN/AlGaN heterostructures exhibit a much small level of 1/f noise than bulk GaN films. In the frame of model linking noise to the tail states, this might be explained by a high degeneracy of the 2D electrons in this structures. Due to the electron degeneracy, the tail states mechanism of the 1/f noise is suppresed in GaN-based 2D structures. Our measurements show that contacts does not contribute much to overall low frequency niose. Concentration dependence of the Hooge parameter points out to the tunneling mechanism of noise in these structures.