Objective:Although many studies have shown association of obesity and breast cancer,the association with the axillary lymph node status is not clear. We examined the relationship of the axillary lymph node status and obesity and other possible factors in breast cancer patients. Methods:In this retrospective cohort study,306 breast cancer patients were included. Patients were grouped according to their body mass index (BMI) values at the time of diagnosis. We analyzed the relationship between BMI and patient and tumor characteristics,especially axillary lymph node status. Results:The median patient age was 48 years(range 21~81). Median BMI of the patients was 25.1 and 54.4%(N = 166)of them had normal BMI,45.6%(n = 140)were BMI ≥ 25. Of the patients,59.6% had no lymph node metastasis,and 40.4% had lymph node metastasis. The total number of lymph nodes removed was higher in the obese group (BMI≥ 25)and this difference was statistically significant (20.4 ± 11.4 vs. 18.1 ± 10.5,P < 0.01). However,there was no statistically significant correlation between the number of metastatic lymph nodes and BMI(P > 0.05). Conclusion:The number of dissected lymph nodes was higher in obese patients but there was no correlation between metastatic lymph node number and BMI.