BACKGROUND: Indocyanine green (ICG) allows for the real-time visualization of lymphatic drainage and provides favorable performance for sentinel lymph node (SLN) mapping. However, the limited ability of tissue penetration of the near-infrared fluorescence of ICG may lead to the failure of lymph node detection in the traditional open approach of sentinel lymph node biopsy (SLNB) for breast cancer, especially in overweight or obese patients. To accurately and quickly detect SLNs, we applied fluorescence endoscopy with a dual-tracer method using ICG and methylene blue dye (MBD) in SLNB for breast cancer. We conducted this study to assess the feasibility and application value of this method in minimally invasive surgery. METHODS: A total of 117 patients who received dual-tracer injection of ICG and MBD prior to endoscopic SLNB from November 2020 to September 2021 were examined in this study. The number of SLNs identified, the SLN identification rate, the time to identify the first SLN, the procedure duration, and the postoperative morbidity were analyzed. RESULTS: Biopsied SLNs could be identified in 116 patients (99.15%) with an average number of 5.12±1.87 per patient. Blue-stained SLNs were found in 99 patients (84.62%) and fluorescent SLNs in 112 patients (95.73%). A total of 34 patients (29.06%) had positive SLNs. In 6 cases (5.13%), the positive SLNs were only stained with ICG fluorescence. In 1 case (0.85%), the positive SLNs were only blue-stained with no fluorescence staining. The mean durations for the identification of the first SLN and endoscopic SLNB were 7.14±6.31 and 37.75±16.94 min, respectively. Upper-limb lymphoedema was observed 5 cases (4.27%) during a median follow-up period of 10 months. CONCLUSIONS: The fluorescence endoscopy method assisted by dual tracer facilitates SLN detection with a comparatively short procedure duration and low complication rate. This approach could serve as a new method for SLNB for patients with breast cancer.