The purpose of this study was to evaluate the risk factors associated with supraclavicular nodal failure (SCF) in patients with one to three positive axillary nodes treated with breast conserving surgery and axillary dissection without supraclavicular node radiation (S/C RT) to aid in the selection of patients for S/C RT. Two hundred two breast conservation patients with one to three positive axillary nodes on axillary dissection treated with breast irradiation without S/C RT and 20 patients with S/C RT between August 1985 and May 2002 were identified and retrospectively evaluated. The Kaplan-Meier method was used to determine SCF-free and overall survival curves. Risk factors for SCF were examined. The median follow-up from surgery was 72 months (range: 4-195). Nine of 202 patients (4%) failed in the ipsilateral breast, 4 (2%) in the ipsilateral supraclavicular lymph nodes, 4 (2%) in the ipsilateral axillary and/or internal mammary nodes and 30 (15%) distantly. The 5- and 10-year SCF-free survival was 97.92%. The overall survival at 5, 10, and 15 years was 91.35%, 75.58%, and 67.18%, respectively. SCFs were associated with high grade or ER negative cancers, but not with number of positive nodes. Two of the four SCFs were associated with distant metastases, and two with local failures. One patient with a SCF was salvaged and is disease-free at 134 months. The overall low incidence of SCF in patients with one to three positive nodes treated with breast radiation alone after breast conserving surgery and adequate axillary dissection suggests that additional S/C RT is unnecessary in this cohort. When it occurs, supraclavicular nodal failure is often associated with distant metastases.