DNA microarrays are among the key technology enablers for the tumultuous development of biology and medicine triggered by high-throughput genomics. As microarray-based methods for analysis and diagnosis become more pervasive, there is an ever-growing demand for low-cost, highly integrated microarrays for point-of-care usage. This article focuses on fully electronic approaches that integrate DNA sensor arrays and circuits for transduction, amplification, digital conversion, and readout of signals on a single CMOS chip. Prototypes of these devices have obtained promising results.