OBJECTIVES: To identify airway clearance techniques (ACTs) used to treat patients with acute exacerbations of chronic obstructive pulmonary disease (AECOPD) and identify factors underpinning their utilisation, including therapists' knowledge of the literature. DESIGN: Cross-sectional postal survey using Likert scales and multiple-choice responses. SETTING: 112 'large' or 'principal referral' Australian public hospitals. PARTICIPANTS: 189 physiotherapists from 89 hospitals (response rate 81%). MAIN OUTCOME MEASURES: Purpose designed survey measuring self-reported rate of ACT prescription; perception of ACT indications, aims, importance and effectiveness; factors influencing ACT choice; and knowledge of the evidence. RESULTS: Most physiotherapists (123/189, 65%) prescribed ACTs for 60-100% of patients with AECOPDs. The most frequently prescribed ACTs were physical exercise (169/189, 89%), the forced expiratory technique (153/189, 81%) and the active cycle of breathing technique (149/189, 79%). Most were rated highly effective. Physiotherapists who perceived the role of ACTs to be important to patients' overall management (137/189, 73%) and those with less than 5 years cardiorespiratory experience (113/189, 60%) prescribed ACTs significantly more frequently than others. The main factors influencing ACT choice were precautions/contraindications to individual techniques (148/189, 78%) and degree of dyspnoea (136/189, 72%). The primary aim of ACT prescription was to clear sputum (178/189, 94%). Understanding of the evidence for ACTs in AECOPDs was mixed, with 43% citing it as supportive, 30% inconclusive and 19% unsure. CONCLUSIONS: Australian physiotherapists frequently prescribe ACTs for patients with AECOPDs and perceive their role to be important. Physical exercise is frequently prescribed for airway clearance and warrants further investigation.