It may be required to ensure patency of the airway in the lateral position in certain circumstances. We performed a prospective randomized clinical trial investigating the effects of left lateral patient positioning on airway anatomy and subsequent airway management. Laryngoscopic airway examination was performed in anesthetized patients, in the supine and left lateral positions, and in the presence and absence of cricoid pressure. Patients were randomized to airway management via an endotracheal tube or laryngeal mask airway (LMA). The left lateral position resulted in a deterioration of laryngoscopic view in 35% of patients and improvement in none. In the lateral position, failure of airway management occurred in more patients with the endotracheal tube versus LMA (8 of 39 versus 1 of 30; P = 0.03), and the mean time to successful completion of airway management was longer with tracheal intubation compared with the LMA (39 ± 19 s versus 26 ± 12 s; P = 0.002). LMA use results in more reliable airway control compared to tracheal intubation in the lateral position. The LMA should be considered as the primary airway device when instituting airway management in this position.