Aim The American Society of Anesthesiologists scale is used worldwide for the assessment of the physical status of patients proposed for anaesthesia interventions. This study aims to assess the level of agreement of the last updated American Society of Anesthesiologists classification version, with the introduction of examples for each class, and search for variables that could promote inconsistency.Methods An online questionnaire was sent to anaesthesiology specialists and residents in Portugal, describing 10 fictitious clinical cases. Sociodemographic and labour data were also correlated. Results/findings:A total of 243 anaesthesiology physicians participated. There was a high diversity in responses. Years of practice influence this diversity (P < 0.05). Discussion and conclusions:The need for a universal scale for classification of patients proposed for anaesthesia is consensual. Despite the last update in 2014, the American Society of Anesthesiologists classification continues to present limitations regarding consistency and objectivity. Efforts should be made to reduce their interpersonal variability.