Objective: To explore the consistency between self perceived body size and body mass index (BMI) evaluation among medical students, and analyze their association with depressive symptoms, so as to provide scientific evidence for psychological intervention targeting medical students. Methods: From September to November 2022, a convenient cluster sampling method was employed to select 1 850 college students from two universities in Hefei, Anhui Province, and Nanjing, Jiangsu Province. The Patient Health Questionnaire-9 (PHQ-9) was used to assess their depressive symptoms. Chi-square test was applied to compare the rates of depressive symptoms among medical students with different demographic characteristics. Kappa consistency test was performed to evaluate the consistency between self-perceived body size and BMI evaluation. Generalized linear models with binomial distribution and Logit link were constructed to analyze the associations of self-perceived body size and consistency between self-rated and BMI evaluation with depressive symptoms, as well as gender differences in these associations. Results: A total of 40.7 % of medical students overestimated or underestimated their body size. Specifically, the underestimation rate was 20.5% in males and 4.9 % in females, while the overestimation rate was 12.7% in males and 40.5% in females, the distribution of consistency in the misclassification rate of body self-perception between males and females was statistically significant ( χ 2=221.54, P ＜0.01). The overall consistency between self perceived body size and BMI evaluation was low for both males and females, with Kappa values of 0.518 and 0.281 respectively (both P <0.01). After adjusting for confounding variables, generalized linear model analyses showed that medical students with self perceived obesity and body size overestimation had higher risks of depressive symptoms ( OR =1.62, 1.26, both P ＜0.05). Stratified analyses by gender revealed that girls with self perceived overweight and obesity had higher risks of depressive symptoms in female students ( OR =1.43, 1.66, both P <0.05), whereas no statistically significant associations among boys ( OR =0.84, 1.86, both P >0.05). Girls with body size overestimation had a higher risk of depressive symptoms ( OR=1.20, P ＜ 0.05), with no significant association in boys ( OR=1.00, P >0.05). Conclusions Differences exist related between self perceived body size and BMI evaluation among medical students. Self perceived obesity and body size overestimation are related factors to depressive symptoms.