Drawing on data from the 2008 Chinese Internal Migration and Health Survey,we compare various health indicators among rural residents who never migrated,return migrants,current rural-to-urban migrants,and urban residents.Two health selective mechanisms,the healthy migrant hypothesis and the salmon bias hypothesis,are empirically tested.Results provide empirical support to both these hypotheses.After controlling for individual’s age,sex,socioeconomic status and major health-related behaviors,rural-to-urban migrants are better off than rural residents who never migrated regarding their self-rated general health,chronic medical conditions,self-perceived physical discomforts and lung capacity.Current rural-to-urban migrants are also less likely to have chronic diseases or to report physical discomforts than return migrants.Except for self-reported chronic conditions and abnormally high heart rate,there is no significant difference in health status between rural-to-urban migrants and urban residents.