The Glidescope Video Laryngoscope (Glidescope, Verathon Medical, Bothell, WA, U.S.A.) is a relatively new intubating device. It has been proposed to be useful for securing both routine airways and those where direct laryngoscopy may be difficult. In this prospective observational study, data for 742 intubations using the Glidescope were collected to investigate whether four factors are associated with successful tracheal intubation at first attempt using the Glidescope: previous Glidescope experience, previous direct laryngoscopy experience, level of anaesthesia training and clinical airway assessment. The likelihood of successful tracheal intubation at first attempt using the Glidescope increased with increasing previous Glidescope experience. Similarly, success was more likely in airways that were assessed as normal compared with those where direct laryngoscopies were either predicted or known to be difficult. Subgroup analysis indicated 83% first attempt success by 'experienced' Glidescope users in patients with documented difficult direct laryngoscopies. This supports its use as an adjunct device for management of airways where direct laryngoscopies prove difficult. With regard to the level of anaesthesia training, only medical students were more likely to fail with the Glidescope. Success was not associated with previous experience in direct laryngoscopy. The lack of association with direct laryngoscopy experience and level of anaesthesia training (beyond student level) suggests that expertise with traditional airway tools is not necessary to become proficient with the Glidescope.