This paper presents an attractive and new quadrature oscillator based on G(m)-C structure. The proposed quadrature oscillator is achieved with MOS transistors and two capacitors. The passive capacitors are grounded, which is an advantage for integrated circuit implementation. The theoretical results are verified by LTSPICE simulation using the 0.18 mu m CMOS technology from TSMC. The proposed quadrature oscillator circuit can be used in several communication and instrumentation systems.