[en] Elastic and inelastic cross sections in H-He collisions have been measured by means of time-of-flight techniques at moderate energy (0.3 to 1.5 KeV). The dominant inelastic process appeared to be the excitation of hydrogen. Large cross sections are found for n = 2 and also for n >= 3 hydrogen excitation. On the other hand, no significant excitation of the helium atom could be observed. A simple two-state quasimolecular model has been used to compute differential and total cross sections for n = 2 excitation of the H atom which agrees satisfactorily with the experiments. (author)