© The Institution of Engineering and Technology. The use of complementary split-ring resonators (CSRRs) as radiating elements in low-profile on-metal ultra-high-frequency radio-frequency identification (UHF-RFID) tags is explored in this study. First, the radiation properties of the edge-coupled and the non-bianisotropic (NB-CSRR) versions of the CSRR are studied. The tag design strategy is then discussed in detail. On that basis, a compact (λ0/7 × λ0/7) low-profile (1.27 mm) tag prototype based on the non-bianisotropic version of the CSRR (NB-CSRR) antenna is designed and manufactured to operate in the North-American UHF-RFID band. The experimental results validate the theoretical and simulated behaviour, and exhibit a maximum read range of 6.8 m.