Two pedunculate oak (Quercus robur L.) populations were grown in a semi-controlled conditions and were subjected to different tratments: optimal soil moisture (control), drought followed by recovery of optimal soil moisture (S1) and permanent drought treatment (S2).Variation in leaf gas exchange parameters such as photosynthesis (A) and transpiration intensity (E), stomatal conductance (gs), instantaneous water use efficiency (WUE) as well as intrinsic water use efficiency (WUEi) were investigated among populations in their response to water deficit and recovery from drought. The results of the study indicate specific adaptive predispositions of examined populations in relation to drought stress and recovery, which provides reliable guidance for assessing their potential for cultivation under water deficiency conditions and the possibility of recovery after re-establishing optimum water supply.