We investigated the artefacts created during magnetic resonance imaging by five different laryngeal mask airways: the Classic (cLMA); the LMA ProSeal; the LMA Unique; the Ambu Disposable Laryngeal Mask; the LMA Supreme; and one other supraglottic airway device, the i-gel supraglottic airway. The devices were placed on top of and inside a phantom simulator to resemble the position in vivo. The artefacts with the cLMA, Unique and Supreme were similar and related to ferromagnetic material in the pilot balloon valve. Artefacts were more prominent with the ProSeal. There were no artefacts with the Ambu Disposable Laryngeal Mask or the i-gel.