Hydrogen insertion into LiNbO2 was carried out using the hydrogen spillover method. The hydrogen inserted compounds, HxLiNbO2, exhibited superconductivity below 5.5 K; this is the same critical temperature as for the delithiated compounds, LixNbO2. Thus, LiNbO2 becomes a superconductor not only from hole doping during delithiation, but also from electron doping during hydrogen insertion. (C) 2000 Elsevier Science Ltd. All rights reserved.