The effect of external stress exerted by enhanced (up to 1.5 GPa) hydrostatic pressure (HP) of argon ambient during annealing of oxygen-implanted silicon (oxygen dose =<1x10 1 7 cm - 2 ) up to 1470 K on oxygen agglomeration has been investigated by secondary ion mass spectrometry, transmission electron microscopy, and X-ray and photoluminescence methods. HP treatment results in oxygen distribution shift and massive creation of oxygen precipitates, whereas creation of dislocations is strongly suppressed.