 This paper presents a novel approach to fabricating 3D micro-electrode arrays using two-photon lithography and traditional silicon thin film processing techniques. The resulting 3D electrode arrays are capable of capturing electrophysiological signals from both birds and mice and can be used in applications such as small animal models, nerve interfaces, retinal implants, and other devices requiring compact, high-density 3D electrodes. This article was authored by Morgan A. Brown, Cara M. Zappatelli, Love Pritzing, and others.