TiNi alloys are potentially able to include in their structure a significant quantity of hydrogen which allows them to be used as electrodes in hydrogen batteries providing their electrical characteristics are suitable, TiNi alloys were produced in hyperquenched tape shape. These tapes were then electrolytically hydrided. X-ray analysis of hydrided and nonhydrided samples was performed. In the hyperquenched tape the B2 and the "R"(H) phases, the presence of which is linked to the hyperquenched constraints, coexist. The hydrided electrolytically hyperquenched tape has the TiNiHx (x = 0.3) formula and contains the two hydrided forms corresponding to those that are unhydrided. At around 100 degrees C, under hydrogen gas, the quadratic hydride parent of B2 remains alone. The TiNiH0.3 sample has been analysed using differential calorimetry under argon and hydrogen gas. In the cubic structure only two octahedral sites are occupied by hydrogen. In TiNiH0.3 only the smaller octahedral sites are occupied by electrolytic hydrogen. If TiNiH0.3 is then charged with hydrogen gas, this gas occupies the other larger octahedral site. The hydride has the formula TiNiH0.85.