BACKGROUND: Regional infusion therapy with melphalan (LPAM) is an accepted treatment for advanced extremity melanoma. However, much room exists for improving the therapeutic index of this type of therapy. METHODS: Isolated limb infusion (ILI) with temozolomide (TMZ), a novel methylating agent, was performed using a nude rat bearing human melanoma xenograft. Additional rats were treated systemically with TMZ, or regionally with LPAM or 10% dimethyl sulfoxide (DMSO; control) using ILI. RESULTS: Rats that received systemic TMZ showed a poor tumor response and no tumor regression. In contrast, intra-arterial TMZ demonstrated a prolongation of tumor growth delay in a dose-responsive manner. In comparison with LPAM of equitoxic dose, TMZ provided both longer tumor growth delay and a greater number of tumor regressions. CONCLUSIONS: These data suggest that ILI with TMZ is an effective treatment for advanced extremity melanoma and may be better than LPAM in this setting.