Storage of gases under pressure, including hydrogen, is a well-known technique. However the use in vehicles of hydrogen at pressures much higher than those applicable in natural gas cars still requires safety and performance studies with respect to the verification of the existing standards and regulations. The JRC-IE has developed a facility, GasTeF, for carrying out tests on full-scale high pressure vehicle?s tanks for hydrogen or natural gas. Typical tests performed in GasTeF are static permeation measurements of the storage system and hydrogen cycling, in which tanks are fast filled and slowly emptied using hydrogen pressurised up to 70 MPa, for at least 1000 times according to the requirements of the EU regulation on type-approval of hydrogen-powered motor vehicles. Moreover the temperature evolution of the gas inside and outside the tank is monitored using an ad-hoc designed thermocouples array system. This paper reports the first experimental results on the temperature distribution during hydrogen cycling tests.