ABSTRACT Stable recordings are a precondition to understanding the fundamental role of long-term brain processes involved in neural plasticity, learning, pathogenesis, and aging. Despite recent advances in materials engineering, digital signal acquisition, and analysis algorithms, stable recording from isolated neurons over longer periods of time remains a challenge. In this study, we combined advances in material chemistry and surgical technique to develop a "Magdeburger" multi-tetrode array that enables parallel recording of multiple single-neurons with long-term signal stability and high signal-to-noise ratio at a reasonable cost. Flexible platinum-iridium tetrodes were electrochemically roughened and coated with carbon nanotubes, thereby decreasing electrode impedance and increasing charge transfer. Packaging of multi-tetrode arrays, tetrode rigidity, and insertion techniques were optimized to minimize tetrode tip movement and to allow simultaneous recordings from independently targeted brain regions even at greater depths in both rodents and primates. Together, the Magdeburger probe provides a basis for a wide range of experimental and translational approaches that require long-term-stable and simultaneous high-quality recordings across different structures throughout the mammalian brain. Areas of potential application include cognitive learning and memory, aging, pathogenesis, neural correlates for behavioral performance, and the development of neuronal brain-computer interfaces for humans.