The importance of dystrophin and its associated proteins in normal muscle function is now well established. Many of these proteins are expressed in nonmuscle tissues, particularly the brain. Here we describe the characterization of β-dystrobrevin, a dystrophin-related protein that is abundantly expressed in brain and other tissues, but is not found in muscle. β-dystrobrevin is encoded by a 2.5-kb alternatively spliced transcript that is found throughout the brain. In common with dystrophin, β-dystrobrevin is found in neurons of the cortex and hippocampal formation but is not found in the brain microvasculature. In the brain, β-dystrobrevin coimmunoprecipitates with the dystrophin isoforms Dp71 and Dp140. These data provide evidence that the composition of the dystrophin-associated protein complex in the brain differs from that in muscle. This finding may be relevant to the cognitive dysfunction affecting many patients with Duchenne muscular dystrophy.