Pressure-composition isotherms for hydrogen absorption and desorption are determined for Nb1-xCrx (x = 0.03, 0.05, 0.1) over the temperature range 320 to 370 K. Pronounced hysteresis are observed at all temperatures. The average enthalpies ([H]/[M] = 0.2-0.8) for hydride formation are -14.0, -14.7 and -15.9 kJ/mol H and for hydride decomposition are 23.4, 23.6 and 22.7 kJ/mol H for x values of 0.1. 0.05 and 0.03. The hysteresis effect is explained in terms of an elastic strain energy effect. (C) 2000 International Association for Hydrogen Energy.