Size miniaturization of microwave filters is highly desirable in the today's rapid changing communications world. Split ring resonators (SRRs) have attracted much interest in recent years as key constituent particles for the design of effective media with negative magnetic permeability (µeff < 0) or left-handed materials (LHM). This paper demonstrates the potential of the sub-wavelength (i.e. electrically very small) split ring resonators and complementary split ring resonators (CSRRs) inclusions to build compact microstrip band stop filters to reject the unwanted spurious bands in microwave regime. It is simple and compatible with MMIC and PCB technology. Moreover, the magnetic coupling between the SRRs and the microstrip line is also investigated. Numerical calculations of the scattering parameters (S-parameters) are performed using the Method of Moments (MoM)-based electromagnetic solver of Ansoft Designer™ software.