Despite the favorable association of components of "dietary approaches to stop hypertension (DASH)" diet and breast cancer (BC), limited data are available linking the whole DASH diet to BC. The aim of the present study was to examine the association between adherence to DASH eating plan and odds of BC in Iranian women. This population-based case-control study was conducted among women aged ≥30 years, who were residing in Isfahan, Iran. Cases were 350 patients with newly diagnosed stage I-IV breast cancer, for whom in-situ or invasive status of BC was confirmed by physical examination and mammography. Controls were 700 age-matched apparently healthy individuals who were randomly selected from general population. Dietary data were collected using a validated 106-item Willett-format semi-quantitative dish-based food frequency questionnaire. To investigate participants' adherence to DASH diet, we created DASH scores based on foods and nutrients emphasized or minimized in the DASH diet. After controlling for potential confounders, individuals in the highest quartile of the DASH diet score had 85% lower odds of breast cancer than women in the bottom quartile (OR: 0.15; 95% CIs: 0.09-0.24). Stratified analysis by menopausal status revealed such association in postmenopausal women (OR: 0.11; 95% CI: 0.06-0.19), but not in premenopausal women (OR: 0.60; 95% CI: 0.14-2.59). In addition, when stratified by BMI status, we found statistically significant inverse association between adherence to the DASH eating pattern and odds of breast cancer among normal-weight (OR for comparing extreme quartiles: 0.13; 95% CI: 0.07-0.24; P-trend < 0.001) and obese women (0.13; 0.05-0.34; P-trend < 0.001). In conclusion, our findings indicated an inverse association between adherence to the DASH eating plan and odds of breast cancer among Iranian women. Further, prospective studies are required to confirm our findings.