Photochemotherapy, consisting of the oral administration of psoralens plus long-wave ultraviolet radiation (PUVA), involves standing in a warm light cabinet for a prolonged time. This study was done to evaluate the cardiovascular reactions in normal patients and in patients with cardiac disease receiving PUVA therapy. Of forty patients studied, six had cardiovascular disease and sixteen had essential hypertension. Holter monitoring during treatment revealed no significant arrhythmias. All patients had a modest increase in heart rate at the end of PUVA, with a mean increase of 22% of baseline. Blood pressure was not significantly changed, and 12-lead electrocardiograms done in twenty-two of the patients before and after PUVA showed no significant changes. Our patients, including those with cardiovascular disease and hypertension, tolerated the PUVA therapy without significant subjective reactions and without evidence of excessive cardiovascular stress.