Background: To evaluate the clinicopathologic and demographic characteristics of triple-negative breast cancer (TNBC) patients and to determine differences from non-triple-negative cases. Materials and Methods: A detailed review of the medical records of 882 breast cancer (BC) patients was conducted to obtain information regarding age, menopausal status, height and weight at the time of diagnosis, presence of diabetes or hypertension, and pathologic characteristics of the tumor (tumor size, lymph node status, histologic grade, ER status, PR status, HER2 status, p53 mutation). Body mass index (BMI) was calculated and a value of ${geq}30$ was considered as indicative of obesity. Results: 14.9% (n=132) of the patients had TNBC. There was no difference among the patients in terms of median age, comorbid conditions and menopausal status. The proportion of medullary, tubular and mucinous carcinomas was significantly higher (15.9%) in the triple-negative (TN) group, while invasive lobular histology was more frequent (8.2%) among non-triple negative (NTN) cases (p<0.001). Grade 3 (G3) tumors were more frequent in the triple-negative group (p<0.001). The rate of p53 mutation was 44.3% in TN tumors versus 28.2% in the NTN group (p<0.001). The two groups were similar in terms of LN metastasis. In the NTN group, the rate of patients with BMI ${geq}30$ was 53% among postmenopausal patients, while it was 36% among premenopausal women, and the difference was statistically significant (p<0.001). No significant difference was observed in terms of BMI between postmenopausal and premenopausal patients in the TN group (p=0.08). Conclusions: TNBC rates and clinicopathologic characteristics of the Turkish patient population were consistent with the data from Europe and America. However, no relationship between obesity and TNBC was observed in our study. The association between TNBC and obesity needs to be evaluated in a larger patient population.