Background: Sentinel lymph node biopsy is used as an accurate staging procedure to detect early breast cancer. Several studies have documented that sentinel lymph node biopsy can accurately determine the status of axillary nodes. Sentinel node biopsy offers the advantage of accurately staging the axilla and eliminating the need for a full axillary dissection for patients who have a negative sentinel node. The aim of this study is to determine the predictors of non-sentinel lymph node metastasis by sentinel node biopsy.Methods: In this study, all patients (n=88) who underwent sentinel node biopsy for invasive breast cancer from June 2005 to June 2010 in Shahid Faghihi Hospital, Shiraz, Iran were enrolled. We reviewed the medical files of patients and their tumor characteristics. Statistical analysis was performed to determine whether any of these characteristics alone could accurately predict the remaining non-sentinel node status. SPSS statistical package was used.Results: The mean age of the patients was 46.1 years. Tumor size was 2.73 cm. Of the 88 patients who underwent complete axillary node dissection, 34 had metastases in the non-sentinel nodes, with a mean of 4 positive non-sentinel nodes in each patient. Statistically, neither the patient’s age nor the clinicopathological features of the tumor were significantly associated with non-sentinel node metastases (all: P>0.05).Conclusion: Our study shows that neither the primary tumor characteristics nor the size of metastasis in the sentinel lymph node can predict the status of non-sentinel nodes. However, further investigation is necessary. Complete axillary node dissection should remain the most appropriate management for patients with positive sentinel lymph nodes.