The effect of cadmium on some major physiological processes in timothy (Phleum pratense L.) was studied in a greenhouse experiment. After 40 days of exposure to 40 mg/kg cadmium the plants demonstrated growth inhibition, which was the most pronounced in the above-ground organs. Cadmium also reduced the content of green pigments, but the functional activity of the plants’ photosynthetic apparatus remained high. We found also that treatment with the metal increased the number of stomata per unit leaf area, and promoted the transpiration rate and stomatal conductance, although the water content in the organs remained unaffected. The results prove timothy is highly resistant to the metal owing to the structural and functional modifications targeted at maintaining the high rate of photosynthesis and adequate water balance.