Objective  To investigate the knowledge of nutrition, attitudes, and behaviors of medical students with non-nutrition majors at universities in Shanghai, analyze factors that affect dietary behaviors of students, and provide evidences for developing nutrition and health education for medical students. Methods  According to relevant literature, a total of 398 medical students with non-nutrition majors at four universities in Shanghai were randomly selected. Questionnaire was designed to conduct the sampling survey of the knowledge of nutrition, attitudes, and behaviors and scores of the knowledge of nutrition, attitudes, and behaviors were analyzed. Results  A total of 377 valid questionnaires were returned form 398 medical students with non-nutrition majors. Most of them lacked nutrition knowledge and the scores were 16.05±3.02. Their attitudes were active and the scores were 21.74±4.14, while dietary behaviors were unsatisfactory and the scores were 19.95±5.08. Scores of attitudes and behaviors of female students were higher than those of male students (P<0.001 and P<0.05). Students with normal BMI accounted for 74.54%. The knowledge of nutrition was positively correlated with attitudes, and behaviors (r=0.157, P=0.002; r=0.250, P=0.000). Conclusion  Medical students with non-nutrition majors in Shanghai commonly lack knowledge of nutrition and their behaviors are unsatisfactory. It is necessary to provide nutrition intervention courses, improve the understanding of nutrition, strengthen education and guidance of behaviors, and enhance the consciousness of nutritional therapy of medical students for future medical practices.