We report a syngeneic model of spontaneous metastatic B16-F10 mouse melanoma in C57/BL6 mice with a very high metastatic frequency that mimics clinical metastatic melanoma. The B16 melanoma cells were injected between the skin and cartilage on the dorsal side of the ear. The model generated lymphatic and visceral metastases in all of the tested animals. In mice with large primary tumors, tumor weight correlated with the tumor growth time and also with the number of metastases in lymph nodes and organs. The dorsal ear space between the skin and cartilage enables both lymphatic and hematogenous metastatic spread. The model should be useful to study the mechanism of melanoma metastasis and to develop therapy for this currently untreatable disease.