This study intends to investigate the correlations of miR-124a and miR-30d with clinicopathological features of breast cancer (BC) patients with type 2 diabetes mellitus (T2DM). A total of 72 BC patients with T2DM (diabetic group) and 144 BC patients without T2DM (non-diabetic group) were enrolled in this study. Blood glucose was detected by glucose oxidase methods. Glycosylated hemoglobin (HbA1c) was measured by high performance liquid chromatography. Fasting insulin (FIns) was measured by chemiluminescent microparticle immunoassay. Automatic biochemical analyzer was used to detect triglyceride, total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C) and low-density lipoprotein cholesterol (LDL-C). Estradiol (E 2 ) was detected by radioimmunoassay. Homeostasis model assessment was applied to assess the insulin resistance (HOMA-IR) and β-cell insulin secretion (HOMA-IS). The expressions of miR124a and miR-30d were measured by quantitative real-time polymerase chain reaction (qRT-PCR). There were significant differences in age, the ratio of menopause, body mass index (BMI), HDL-C, TC, 2-h plasma glucose (2hPG), FIns, HbA1c, HOMA-IS and HOMA-IR between the diabetic and non-diabetic groups. The diabetic group had higher incidence of lymph node metastasis than non-diabetic group. The miR-124a expression was down-regulated while the miR-30d expression was up-regulated in BC patients with T2DM. The correlation analysis showed that miR-124a expression was positively correlated with HDL-C, while it was negatively correlated with age, HbA1c, LDL-C and E 2 . However, the miR-30d expression was negatively correlated with HDL-C but positively correlated with age, HbA1c, LDL-C and E 2 . In conclusion, miR-124a and miR-30d may be correlated with clinicopathological features of BC patients with T2DM. The miR-124a and miR-30d could serve as novel biomarkers for early diagnosis of BC in patients with T2DM.