Pulse oximetry is mandatory during anaesthesia in many countries, a standard endorsed by the World Health Organization 'Safe Surgery Saves Lives' initiative. The Association of Anaesthetists of Great Britain and Ireland, the World Federation of Societies of Anaesthesiologists and GE Healthcare collaborated in a quality improvement project over a 15-month period to investigate pulse oximetry in four pilot sites in Uganda, Vietnam, India and the Philippines, using 84 donated pulse oximeters. A substantial gap in oximeter provision was demonstrated at the start of the project. Formal training was essential for oximeter-naïve practitioners. After introduction of oximeters, logbook data were collected from over 8000 anaesthetics, and responses to desaturation were judged appropriate. Anaesthesia providers believed pulse oximeters were essential for patient safety and defined characteristics of the ideal oximeter for their setting. Robust systems for supply and maintenance of low-cost oximeters are required for sustained uptake of pulse oximetry in low- and middle-income countries.