Introduction: Mindful eating is being fully present in the moment of eating and it is critical in preventing poor eating habits. The main objective for this study was to determine the associations of body mass index (BMI) and physical activity level with mindful eating behaviour among undergraduate medical students of Universiti Sains Malaysia (USM), Health Campus, Kubang Kerian, Kelantan. Methods: A cross-sectional study was conducted among 158 students (Years 1-5; 69% females and 31% males) by using a self-administered online questionnaire consisting of socio-demographic data, anthropometric data, short version of the International Physical Activity Questionnaire (IPAQ), and Mindful Eating Questionnaire (MEQ). The associations between BMI and physical activity with MEQ were determined by Spearman’s Correlation and One-Way ANOVA or Kruskal-Wallis Test, respectively. Results: Majority of the students had normal BMI (66.4%, n=105), and 39.9% (n=63) had low physical activity levels. The mean MEQ summary score of the students was considered high (2.82±0.26). There was a significant negative association between MEQ summary score (r=-0.191; p=0.016) and disinhibition subscale score (r=-0.340; p<0.001) with BMI, whereby MEQ summary and disinhibition subscale scores increased as BMI decreased. However, there was no significant association between physical activity level with MEQ score (p>0.05). Conclusion: A student with positive mindful eating behaviour has the potential to lower his/her BMI. However, further research is required to verify this finding.