Introduction: The axillary lymph node status is a powerful predictor of overall survival in patients with breast cancer.The sentinel lymph node is the first node to receive lymphatic drainage.The combination of radiocolliod isotope and blue dye is the ideal technique in the mapping of the sentinel node.However, the use of radiocolliod isotope involves radioactive substances, lymphoscintigraphy and nuclear medicine expertise, making it expensive and logistically difficult to employ routinely.Several studies have shown that using blue dye only technique is comparable to the combined method (Marrow et al 1999).However, the blue dye used for lymphatic mapping, lymphazurin 1%, has caused anaphylactic reaction and interferencewith pulse oximetry.Objectives: The aim of this trial is to determine the sensitivity rate of sentinel node mapping using blue dye alone technique and to compare the rate between lymphazurin 1% (isosulfan blue) and methylene blue.Materials and Methods: There were 200 patients with invasive breast cancer randomised into group A, receiving lymphazurin 1% (98 patients) and group B receiving methylene blue (102 patients).The blue dye was injected in the periareolar region.The sentinel node(s) was defined as the blue node.Patients underwent mastectomy or breast concervation surgery with routine axillary clearance after the removal of the blue node.Results: The overall the sentinel node identification rate was 97% (194/200), false negative rate was 6.6% (5/76)and accuracy rate was 95.9% (186/194).In group A, the sentinel node identification rate was 97.9% (96/98), false negative rate was 7.5% (3/40) and accuracy rate was 96.8% (91/94).In group B, the sentinel node identification rate was 96.1% (98/102), false negative rate was 5.6% (2/36) and accuracy rate was 95% (95/100).Conclusion: Sentinel node mapping with blue dyes alone is feasible and accurate.Lymphazurin 1% and methylene blue had comparable results.