The Lymphatic Microsurgical Preventing Healing Approach (LYMPHA) procedure entails performing a lymphovenous bypass (LVB) at the time of axillary lymph node dissection to reduce lymphedema risk. The two most common fluorophores utilized in LVB are blue dye and indocyanine green. We developed a novel application of fluorescein isothiocyanate for intraoperative lymphatic mapping. Our goal is to demonstrate the safety and efficacy of fluorescein isothiocyanate for this application. We reviewed a prospectively collected database on breast cancer patients who underwent LYMPHA from March to September 2015. Fluorescein isothiocyanate was used to identify arm lymphatic channels after axillary lymph node dissection to perform an LVB between disrupted lymphatics and axillary vein tributaries. Data on preoperative and intraoperative variables were analyzed. Thirteen patients underwent LYMPHA with intraoperative fluorescein isothiocyanate lymphatic mapping from March to September 2015. Average patient age was 50 years with a mean body mass index of 28. On average, 3.4 lacerated lymphatic channels were identified at an average distance of 2.72 cm (range, 0.25–5 cm) caudal to the axillary vein. On average, 1.7 channels were bypassed per patient. Eleven anastomoses were performed to the accessory branch of the axillary vein and 1 to a lateral branch. In 1 patient, a bypass was not performed due to poor lymphatic caliber and inadequate length of the harvested vein tributary. No intraoperative adverse events were noted. Fluorescein isothiocyanate is a safe and effective method for intra-operative lymphatic mapping. Fluorescein isothiocyanate imaging allows for simultaneous dissection and lymphatic visualization, making it an ideal agent for lymphatic mapping and dissection in open surgical fields, such as in the LYMPHA procedure.