We identified 475 patients with breast cancer who underwent 478 sentinel node biopsies. Both dye and isotope were given in 418 cases, of which 380 had a positive lymphoscintigram. In 5 of the 380 cases with a positive lymphoscintigram, the sentinel nodes obtained were blue but not hot, for a 1.3% marginal benefit of dye in the technical success of the procedure. Sentinel nodes positive for metastasis were found in 102 of 380 cases; in 3 cases, the only positive sentinel node was blue but not hot