The simulated moving bed (SMB) process, after more than 40 years of successful operation in the petrochemical industry, has emerged as one of the most important separation processes in the pharmaceutical, fine chemical, and biotechnology fields. However, optimal operation and automatic control of the SMB process is still challenging because of its complex dynamics caused by periodic port switching and inherent nonlinearity. In this research, a novel advanced control technique for the SMB process has been proposed. In the proposed technique, regulation of both extract and raffinate purities measured at the terminal time of each switching period is performed by a nonlinear repetitive controller which utilizes the past period data as feedback information. The repetitive controller was designed on the basis of a fundamental nonlinear model of the SMB process. Through application to a numerical SMB process, it was found that the proposed control technique performs quite satisfactorily against model error as well as set point and disturbance changes.