Objective To describe the levels of knowledge of and attitudes to organ donation among ICU medical staff in Guizhou province and to analyze the influencing factors. Methods A questionnaire survey was conducted among 926 ICU physicians and nurses in Guizhou province. Results The scoring rate of knowledge of organ donation was 51.66% and that of attitude was 73.17%. Education level, residence, gender,political status, age, work length and occupation were factors affecting knowledge of organ donation; residence, education level and gender were predictors of attitude to organ donation (P<0.05, P<0.01). Knowledge of organ donation was positively correlated with attitude (P<0.01). Conclusion ICU medical staff in Guizhou province have a positive attitude toward organ donation, but their knowledge needs to be improved. Their knowledge of and attitude to organ donation are affected by several factors. Education should be strengthened to effectively improve the rate of organ donation in China.