Bandstop filters with single and dual stop-bands were implemented using coupled mode microstrip slot resonators (MSRs) for the first time. With compact and ease of fabrication, the MSRs provide excellent filter response as desired. It is found that the MSRs can offer narrow bandwidth of less than 20% fractional bandwidth and large isolation of more than 40 dB. The designs of MSRs and filters are systematically demonstrated with the method of coupled mode resonator theory. MSRs may be potential alternative for complicated and arbitrary design of BSFs to achieve desired frequency response. © 2020 Informa UK Limited, trading as Taylor & Francis Group.