Data of 769 Stage I melanoma patients treated from 1967 to 1974 by the W.H.O. Melanoma Group centers were analyzed. The mean follow-up period was 10.3 years. Of the 769 patients (239 males, 530 females), 133 had a primary in the BANS region. The observed ten-year actuarial survival was 54.8% for the 133 BANS patients and 54.9% for the remaining 636. Multivariate analysis showed that thickness was the most important prognostic factor (P = 10(-9]; ulceration and sex were also found to be significantly related to survival (P values were 5 X 10(-4) and 10(-5), respectively). The other criteria were no longer significant when adjusted by these three. In particular, the BANS region had a P value of 0.6. To evaluate the effect of BANS in thin melanoma, a subgroup of 152 patients (29 BANS, 123 other) with primary thickness between 0.76 and 1.69 mm was studied. Multivariate analysis showed that no criteria are significantly associated with prognosis of these patients. Observed actuarial survival rate for BANS patients was 69.2% and for the remaining 123, 66.7%. The number of deaths was 8/29 and 27/123. The BANS region does not appear to be of importance in the prognosis of Stage I melanoma patients.