Chronically implanted microwire arrays are a simple and reliable tool for long-term multichannel neurophysiological recording and stimulation. Multichannel arrays increase data yield from individual animals and allow questions about higher brain function and functional connectivity to be addressed. These chronically implanted electrodes also allow for greater physical and behavioral freedom of the experimental subject, allowing investigators to perform recordings on awake, behaving subjects in more naturalistic settings. Finally, chronic recording techniques permit long-term access to a block of neural tissue, a fundamental advantage in studies on neural plasticity. Continuing development will provide an inexpensive, uniform, and dependable source for microwire arrays. New manufacturing approaches will allow for greater data yield, more precise electrode placement, consistent impedances across the array, better neural isolation and improved electrode geometry. Designs to improve ease of insertion and long-term biocompatibility will also be developed. Microwire array development is an enabling technology for research on sensory and motor mapping, functional electrical stimulation, chronic neural implants, and neural prostheses.