To evaluate the predictive efficacy and prognostic value of rs7435335 located in the UGT2B7 gene as a genetic marker in breast cancer patients receiving neoadjuvant chemotherapy (NAC). A total of 190 patients with breast cancer treated with NAC were enrolled to detect the rs7435335 SNP by sequenom. Miller-Payne grades were used to evaluate the treatment efficacy. The association between rs7435335 and chemotherapy efficacy and prognosis was analyzed. Altogether, 42 cases (22.1%) achieved pathologic complete response (pCR). The results of the univariate analysis showed that rs7435335 had no statistically significant difference with pCR and Miller-Payne grades (P > 0.05). When grouping was done in accordance with the ER status, the pCR and Miller-Payne grades significantly associated with rs7435335 ( P < 0.05) only in the ER-negative group. Multivariate logistic regression analysis suggested that rs7435335 in the ER-negative group was an independent predictor of pCR ( P < 0.05). Survival analysis showed that the disease-free survival (DFS) time in patients with GA genotype was longer than that of GG genotype, and rs7435335 predicted the DFS in the ER-negative group. The UGT2B7 rs7435335 is associated with the NAC efficacy and prognosis. Patients with GA genotype have better efficacy and prognosis. Rs7435335 was found to be a possible gene marker for pCR and prognosis in ER-negative patients who received NAC.