Inhalation injury is a major cause of morbidity and mortality in thermally injured patients but is difficult to quantify. A number of parameters can be useful evaluating inhalation injury including bronchoscopy, PaO(2)/FiO(2) (P/F) ratio, and carboxyhaemaglobin (COHb) levels. Identification of markers that permit early detection of the degree of damage caused by inhalation injury is important to predict patient survival. In this retrospective study we evaluated the potential of using the P/F ratio, bronchoscopic findings and the COHb level to assess the severity of the inhalation injury in adults. A retrospective review of all patients admitted with inhalation injuries to the intensive care unit (ICU) from January 1995 to December 2002 was conducted and of the 110 patients 105 Casenotes were obtained and investigated. The total burn surface area (TBSA), age and bronchoscopic findings showed a positive correlation with mortality. There was no significant correlation between COHb levels and mortality, but there was a significant correlation between P/F ratio and mortality in adults. Logistic regression indicated that the combination of TBSA, age and P/F ratio was highly predictive of mortality following major burns. This study supports the predictive nature of the P/F ratio in relation to survival in adults. Larger prospective studies using bronchoscopic findings and P/F ratio would give us a better indication as to the value of a scoring system in adults that are admitted with inhalation injuries.