This paper presents a miniature electromagnetic (EM) sensor node for wireless surgical navigation systems. The sensor node measures the intensity of the EM field originated from the EM field generator placed at the predefined position and determines the position and orientation of the object where the sensor node is attached. The wireless electromagnetic sensor node performs analog and digital signal processing as well as wireless communication. The EM field signal from the generator is detected by the LC resonator circuit, and then amplified and filtered in the analog signal processing subsystem. This analog signal is converted to the digital data, and discrete-Fourier-transform analysis is performed in the digital signal processing subsystem. The analysis results are then transferred to the base station by using wireless communication. The developed sensor node is 8.84 cm3 in volume while exhibiting the accuracy of 99.58% and 99.92% for position and orientation sensing, respectively.