Line-1, a weakly immunogenic lung tumor cell line derived from the BALB/c mouse, metastasizes spontaneously to the lungs of mice following subcutaneous administration. The parameters that influence metastasis as well as the progression of metastatic lung disease following surgical resection of primary subcutaneous tumors were characterized. Histological analysis of the lungs obtained from mice bearing different size subcutaneous tumors demonstrated that >90% of the mice developed micrometastatic disease in the lungs when the tumor exceeded 650 mm3 in size. Surgical resection of subcutaneous tumors resulted in the cure of primary disease in 95% of the mice. Macroscopic tumor nodules were grossly visible in the lungs of 75% of the mice 5 weeks after surgery. Serum amyloid A level correlated with primary tumor burden and was diagnostic for the presence of metastatic disease. The efficiency of metastasis, post-surgical primary tumor recurrence and long-term survival were significantly different between BALB/c mice obtained from different suppliers. The Line-1-BALB/c surgical metastasis model provides a clinically relevant tool for the evaluation of anti-cancer therapies, especially those that are designed to target long-term suppression of minimal residual disease following surgical intervention.