Severe kyphoscoliosis can cause chronic respiratory failure. Noninvasive mechanical ventilation (NIMV) is a new optional treatment for such patients. The aim of this study was to evaluate the effectiveness of average volume-assured pressure support (AVAPS) NIMV in patients with kyphoscoliotic chronic respiratory failure. The study was performed in 12 patients (mean age 49±11 years and body mass index 27.5±7.9 kg/m2) with advanced kyphoscoliosis complicated by severe respiratory failure (PaO2 6.68±0.34 kPa, SaO2 81.7±3.1%, PaCO2 9.51±1.08 kPa) treated by the NIMV. The short-term, after 5 days, and long-term, after 1 year of home treatment, efficacy of NIMV was evaluated. We found a significant improvement of diurnal PaO2 and PaCO2 on the 5th day of NIMV (an increase of 1.4±0.3 kPa and a decrease of 1.8±0.8 kPa, respectively; p<0.05) and after one year NIMV (an increase of 2.07±0.46 kPa and a decrease of 2.68±0.85 kPa, respectively; p<0.05). There was a significant increase of mean blood oxygen saturation during sleep on the 5th day (86.2±3.2%) and after 1 year of treatment (89.4±2.1%) compared with the baseline level (83.2±3.2%). The forced vital capacity also increased after 1 year (1,024±258 ml vs. the baseline 908±267 ml; p<0.05). The NIMV was well tolerated and no patient discontinued the treatment during the observation period. We conclude that AVAPS NIMV is an effective treatment option in kyphoscoliotic patients with chronic respiratory failure, resulting in a prompt and long-term improvement of daytime and nocturnal blood gas exchange.