Aspecific bronchial hyperreactivity (A.B.H.) is a condition found mostly in cases of bronchial asthma, but it may also present in other pathologies affecting the respiratory tract. This study examines 30 patients presenting hilo-pulmonary sarcoidosis, 27 asthmatic patients and 25 healthy subjects as controls. The three groups were sex and age matched. No significant difference in smoking habits between controls and sarcoidosis patients was found. Patients were tested for aspecific bronchial hyperreactivity by administering increasing doses of methacholine. Methacholine inhalation was performed following a dosimetric method. Aspecific bronchial hyperreactivity was found in 6 (20.6%) of sarcoidosis patients with a significant frequency (p < 0.05). No statistically significant difference was found for mean PD20FEV1 values, but the difference between asthma and sarcoidosis patients was highly significant (p = 0.003). No statistically significant difference was found between basal FEV1 means expressed as a percentage of the former in asthmatics and sarcoidosis patients, both responsive and unresponsive. Although it is difficult to draw conclusions from these findings, aspecific bronchial hyperreactivity was seen to increase in subjects with sarcoidosis, and this may explain the not rare association between asthma and sarcoidosis.