We retrospectively evaluated the clinical effectiveness of a treatment schedule with intermittent positive pressure ventilation via nasal mask in 49 patients with acute exacerbations of COLD. According to the ability to successfully tolerate a preliminary trial with NIPPV, patients were submitted either to standard treatment plus NIPPV (25 patients) or to ST alone (24 patients). The ST consisted of medical, oxygen and physical therapy. The NIPPV was delivered by a volume cycled ventilator in control mode at least 4 h a day for five consecutive days a week, for three weeks. Comparison of baseline with measurements performed after 10 and 21 days of treatment respectively showed a significant improvement in PaO2 and in PaCO2 in both groups. After 21 days of treatment, VC, FEV1, inspiratory muscle strength, and dyspnea significantly improved in both groups. No significant difference was found between groups at any time of treatment. We conclude that the treatment schedule of NIPPV used is not more effective than ST alone in acute exacerbations of COLD.