Objective · To understand the medical treatment willingness and place among migrant workers in Shanghai and relevant influencing factors. Methods · The questionnaire survey was used to investigate migrant workers in some areas of Shanghai and the data were analyzed with constituent ratio, χ2 test, and Logistic regression. Results · Regional differences in medical treatment willingness and place existed between migrant workers in surveyed areas and local workers. Differences between actual and intended medical treatment places existed among migrant workers. Main factors influencing the medical care seeking behavior of migrant workers were medical insurance, economic factors, and demographic factors. Conclusion · The medical security system and the accessibility of basic medical services for migrant workers should be further improved.