The aim of this study is to compare the brightness of laryngoscope light between instruments, and the variability within the same instrument. A secondary aim is to compare the light from a reusable laryngoscope with a single use design. Testing equipment was constructed which provided a qualitative measure of light output from laryngoscopes. Anaesthetists assessed the minimum acceptable brightness for intubation using the intubating mannikin and a variable brightness laryngoscope. Laryngoscopes in anaesthetic rooms around the hospital were then tested repeatedly, and the results were compared to the anaesthetists' opinions. There was considerable intersubject and intrasubject variation in the reusable design, often failing to satisfy the minimum brightness. The single use blades were found to be brighter and more reliable than reusable blades.