This is a report of respiratory changes following percutaneous cervical (C2) cordotomy for intractable pain, consisting of: (1) a retrospective review of 13/200 patients with respiratory complications; and (2) a prospective study of pulmonary function in 41 patients. (1) Three of 13 patients had sleep-induced apnea following bilateral cordotomy and required artificial ventilation for 1 to 3 months. (2) Following unilateral cordotomy, mean FVC, MEFR and Pao2in all 41 patients were not lowered. Seven of 41 patients developed dyspnea post-cordotomy; two needed temporary artificial ventilation; but 6/7 had greatly reduced pulmonary function pre-cordotomy. Two developed phrenic palsy without dyspnea. Following cordotomy on the second side (17 patients) there was a significant reduction in MEFR, FVC and Pao2values, greater in the 7/17 who became dyspneic Three developed phrenic palsy with dyspnea.