The Buteyko Breathing Technique (BBT) is promoted as a drug-free asthma therapy. It is based on the premise that raising blood PaCO2 through hypoventilation can treat asthma. Our study was designed to examine whether the Buteyko Breathing Technique, as taught by a video, is an efficacious asthma therapy. Thirty-six adult subjects with mild to moderate asthma were randomized to receive either a BBT or placebo video to watch at home twice per day for 4 weeks. Asthma-related quality of life, peak expiratory flow (PEF), symptoms, and asthma medication intake were assessed both before and after intervention. Our results demonstrated a significant improvement in quality of life among those assigned to the BBT compared with placebo (p = 0.043), as well as a significant reduction in inhaled bronchodilator intake (p = 0.008). We conclude that the BBT may be effective in improving the quality of life and reducing the intake of inhaled reliever medication in patients with asthma. These results warrant further investigation.