Cold Pressor Test (CPT) was applied to patients with chronic lung disease, including primary pulmonary hypertension, and the effects on pulmonary circulation were compared to those on systemic circulation. HR PPA, and TPR showed maximum values at the end of CPT (Time = 0) and recovered to baseline values 5 min after CPT. CO, however, did not change significantly after CPT. PPA and PAR showed maximum values at the end of CPT and then gradually decreased, but still were significantly higher than baseline values at 5 min after CPT. Nifedipine (NFP) reduced the maximum values of both TPR and PAR at the end of CPT. There was significant correlation between PPA change after CPT and baseline PPA value, and NFP decreased the slope of the regression line. These results indicate that cold stimulation induces both systemic and pulmonary vasoconstriction in patients with chronic lung disease, and this pulmonary vasoconstriction was correlated to the baseline pulmonary vascular tone. Moreover, nifedipine may reduce this cold stimulation-induced pulmonary vasoconstriction.