We present the measurement of the sticking coefficient of Ba atoms on a MgO substrate by resonant laser induced fluorescence. The substrate is used as a target for a thermal atomic beam of barium while a laser crosses the substrate and counterpropagates to the atomic beam monitoring its velocity profile. A signal corresponding to negative velocity atoms with respect to the beam direction allows to determine the sticking coefficient. It resulted equal to 0.76 ±0.05. ©1995 American Institute of Physics.