The new JET Lower Hybrid Current Drive (LHCD) system has been operational during the 1990 experimental campaign; up to 1.6MW at 3.7GHz have been coupled to 2 and 3MA plasmas in the limiter and X-point configurations. 20 sec long LH pulses have led to steady state plasma conditions with a 50% drop in the loop voltage measured up to ne = 2 1019 m­3. The broadening of the current profile is observed to increase with increasing electron density. Combined operation of Ion Cyclotron Resonance Heating (ICRH) and LHCD has resulted ln current drive efficiencies g = ne ICD R/PLH ~0.4 1020 m­2 A/W at vo1ume averaged e1ectron temperatures of 1.9keV and stabilization of sawteeth up to 2.9sec. LHCD operation is associated with central electron heating at ~1keV/MW at ne ~ 1.8 1019 m­3, while generating a hollow shell of suprathermal electrons, as measured by a newly installed Fast Electron Bremsstrahlung diagnostic.