The kinetics of desorption of hydrogen from the copper component of an alumina-supported polycrystalline copper catalyst has been studied in detail by temperature-programmed desorption (TPD). Line-shape analysis of the hydrogen TPD spectra shows: (i) that the desorption is second order, (ii) that the desorption activation energy is in the range 64-68 kJ mol(-1) in the coverage range 7-44% of a monolayer, and (iii) that the desorption pre-exponential term has a value similar to 10(-5) cm(2) s(-1) atom(-1) consistent with the desorption being second order, involving mobile adsorbates and a mobile desorption transition state.