This double-blind crossover study was designed to compare the effects of felodipine and cilazapril on exercise performance in hypertensive patients. After a 2-week placebo run-in period, 40 patients with mild to moderate hypertension were randomized into two parallel groups to receive either felodipine (10 mg) or cilazapril (5 mg) for 4 weeks. After another 2-week washout period, treatments were then crossed over for a further 4-week study period. All patients were given an extensive rest and exercise evaluation at the end of the placebo period. Extensive rest and exercise evaluations were repeated after a 4-week treatment period and again after the second washout period and after the second 4-week treatment period. Before each exercise test, epinephrine, norepinephrine and dopamine plasma levels and plasma renin activity were measured. Two groups were similar at baseline for systolic and diastolic blood pressure and heart rate as well as for laboratory and hormonal variables and duration of exercise test. At the end of treatment diastolic blood pressure was significantly reduced in the felodipine group (p = 0.019). Duration of exercise test was longer than at baseline (p = 0.031) in the felodipine group. Plasma dopamine levels were significantly increased in the cilazapril group. Plasma renin activity significantly increased in the felodipine group. In conclusion, our data show that the two drugs have the same effectiveness in resting conditions but that felodipine is more effective in lowering maximum exercise diastolic blood pressure and in improving exercise time with an double product increase (not significant); it has no statistically significant effect on maximal exercise systolic blood pressure.