Thoracotomy is generally considered to give rise to very severe pain. Although the efficacy of several new procedures of postoperative pain relief has been emphasized, postoperative pain is still a difficult problem to solve. Since July 1986, cryoanalgesia has been used for the relief of pain after thoracotomy as a routine method of postoperative pain control in our unit. This study showed that the patients who received cryoanalgesia required significantly less narcotics after operation than those who did not receive cryoanalgesia. The effectiveness of cryoanalgesia was verified not only by subjective parameters such as pain, but also by a definite improvement in spirometric parameters and additional benefits attributed to a decrease in the occurrence of postoperative pulmonary complications.These findings suggest that cryoanalgesia has a definite advantage over previous forms of control of postthoracotomy pain, and the additional time needed to apply cryoanalgesia is well justified.