Lower hybrid current drive (LHCD) experiments on JT-60 have been carried out in parameter ;e = (0.6−1.6)×1019 m−3, Ip = 0.5−1.5 MA, BT = 2.7−4.5 T, PLH < 2.5 MW, f = 1.75 and 2.0 GHz, with and without NB heating (PNB < 6 MW), limiter and lower side single null divertor configurations, and narrow and wide spectra. The current drive efficiency increases with the volume averaged electron temperature ⟨Te⟩ and with decreasing Zeff and a high efficiency of ηCD ≡ eRPIRF/PLH ≤ 2.65 × 1019 m−2·A·W−1 was achieved by LHCD alone. The experimental data set has shown that the current drive efficiency is consistent with the scaling of ηCD ∼ 12 ⟨Te⟩/(5+Zeff)×l019 m−2·A·W−1. Low N1 waves with a narrow spectrum have a higher current drive efficiency than higher N1 waves with a wide spectrum insofar as launched waves satisfy the accessibility