The active cycle of breathing techniques (ACBT) in gravity-assisted drainage positions is an effective airway clearance regimen for individuals who produce excess bronchial secretions. This study compared the ACBT in positions with and without a head-down tilt. Nineteen subjects (11 men), mean age 37.1 years (range 18-76 years), with bronchiectasis who produced more than 20 g of sputum per day and had a mean forced expiratory volume in 1 s (FEV1) of 56.9% predicted (range 23-90% pred.) were studied. There was no significant difference in the wet weight of sputum expectorated when using the ACBT in gravity-assisted drainage positions with or without a head-down tilt. Mean (SD) score for perception of breathlessness, measured on a visual analogue scale, increased significantly following treatment with a head-down tilt [2.3 (1.6) to 3.3 (2.0) cm, P = 0.02]. There was no significant difference in oxygenation or lung function (FEV1). Eighteen subjects preferred the ACBT without a head-down tilt. The ACBT in the horizontal position is a simple airway clearance regimen suitable for individuals who produce greater than 20 g of sputum per day. Subjects were less breathless and preferred the ACBT in the horizontal position, thus providing a treatment alternative that may improve adherence in individuals who are required to carry out daily airway clearance treatments.