A sentinel lymph node biopsy is a surgical staging procedure performed for patients with primary cutaneous melanoma who are clinically lymph-node negative to determine whether there is low volume nodal metastasis in the draining lymph node field. A systematic review was recently performed to update the Australian clinical practice guidelines for the diagnosis and management of melanoma, addressing the question, 'When is a sentinel lymph node biopsy indicated?' This article discusses the findings of the systematic review and the evidence base for the updated guidelines.