Aim: The aim of this study was to evaluate the contribution of an early dynamic phase (DP) of the lymphoscintigraphy (LS) to the detection of the sentinel lymph node (SLN) in breast cancer. Methods: This prospective study included 164 breast lesions in 161 consecutive patients (160 women, mean age 57.5 years). Patients with tumor >5 cm, multicentric, palpable nodes, axillary involvement, previous surgery, lymphadenectomy, radio or chemotherapy were not included. All patients underwent preoperative LS before surgery. DP immediately after injection of [99mTc]Nanocolloid followed by early and delayed planar images (EPI and DPI) were acquired. Results: SLN was detected in 162/164 lesions (98.8%). In 115 (71%) DP showed no lymph node uptake and the SLN was identified only by EPI and DPI. A focal uptake by at least one lymph node was observed in DP in the remaining 47 lesions (29%). Although in 30/74 lesions DP did not provide additional information to EPI and DPI, nevertheless in 17 cases (10.5%) DP was essential to identify correctly the SLN. Conclusion: We concluded that DP, by allowing a better interpretation of the lymphatic drainage pattern, provides unique information to distinguish the correct SLN from other lymph nodes and is recommended as the first part of LS.