The combination of preoperative lymphatic mapping with intra-operative probe detection is becoming the standard procedure for identifying tumour lymphatic spread at the time of initial treatment in breast cancer. There are a number of identification techniques for sentinel lymph nodes, but the concordance of the results of a sentinel lymph node biopsy with axillary lymph node dissection did not vary significantly among them. Periareolar (p.a.) injection of tracer is a new procedure specifically studied to overcome some limitations of other techniques; in two groups of patients with early breast cancer we compared the periareolar with the subdermal technique. One hundred and fifty biopsy proven breast cancer patients were consecutively enrolled in this study. This population was divided into two groups: (1) group A, including 100 cancers; lymphatic mapping was performed by s.d. injection of both blue dye and radiotracer; and (2) group B, including 50 cancers; lymphatic mapping was performed with a combination of blue dye injected p.a. and radiotracer injected s.d. For group A, with both techniques we identified one or more SLNs in 100/100 tumours; blue dye detected the SLNs in 99/100 cancers (99%), lymphoscintigraphy in 93/100 cancers (93%). The concordance rate was 92%. For group B, with both techniques we identified one or more SLNs in 49/50 cancers (98%); blue dye detected the SLNs in 48/50, lymphoscintigraphy in 46/50 cancers (92%). The concordance rate was 92%. In the present study p.a. and s.d. injection of blue dye give similar and comparable results. The periareolar technique is simpler and has several advantages over the subdermal technique.