An energy-efficient epileptic seizure detection system-on-chip (SoC) is integrated in 10.41mm2 in 0.18μm CMOS. The chip integrates analog frontend, a 16-bit ADC, a 32-bit processor, hardware accelerators, and data control unit (DCU) for epileptic signal processing. A 32.8x processing time reduction and an 8.5x energy reduction are achieved through hardware-software co-design. The chip dissipates 28.6μW with a detection accuracy of 93.1% within 0.72 seconds at 1V. It achieves ASIC-like energy efficiency with higher detection accuracy and shorter detection latency.