Purpose: Mammography is the cornerstone of breast cancer (BC) evaluation. This report investigates whether breast density (BD) and mammographic features of the tumor can provide information on both BC susceptibility to chemotherapy and other clinicopathologic features of locally advanced BC (LA BC). Materials and methods: We evaluated mammography films and clinicopathological information of patients with LA BC who received neoadjuvant chemotherapy (NAC) followed by tumor resection at the Instituto Nacional de Enfermedades Neoplásicas (INEN) from 2000 to 2011. Results: We selected 494 LA BC cases. Most cases were at clinical tumor stage 4 (48.5%), node stage 1 (58.8%) and had high histologic grade (53.3%). BI-RADS 1, 2, 3, and 4 BD were found in 16.9%, 22%, 35.7% and 25.1% of patients, respectively. High BD has been associated with younger age (p < 0.001), obesity (p = 0.017) and no skin...