Fifteen-day-old bean plants (Phaseolus vulgaris L.) grown in a climatic chamber were exposed to water deficit (WD) and high temperature (HT) stresses applied separately or in combination. Changes in chlorophyll fluorescence quenching were investigated. Bean plants that endured mild (42 °C, 5 h for 2 d) WD separately or in combination with HT did not change their qP and qN quenching (measured at 25 °C) compared with those of the control. After 5 min testing at 45 °C, qP in control and droughted plants strongly decreased, while qP of plants that experienced combined WD+HT stress was insignificantly influenced, suggesting the acclimation effect of HT treatments. At more severe stresses (after 3 d-treatment), qP measured at 25 °C was the lowest in WD+HT plants and qN values were the highest. But when measured at 45 °C, qP of WD+HT plants had practically the same values as at 25 °C. Under these conditions qP of WD plants also showed an adaptation to HT. Twenty-four hours after recovery, the unfavourable effects of the stresses were strongly reduced when measured at 25 °C, but they were still present when measured at 45 °C. Positive effect of the carbamide cytokinin 4-PU-30 was well expressed only in droughted plants. and I. Yordanov, V. Velikova, T. Tsonev.