In a previous study from our laboratory, high tumor levels of tissue inhibitor of metalloproteinases-1 (TIMP-1) have been associated with an adverse response to chemotherapy in metastatic breast cancer suggesting that TIMP-1, which is known to inhibit apoptosis, may be a new predictive marker in this disease. The purpose of this study was to investigate the association between TIMP-1 and objective response to chemotherapy in an independent patient population consisting of patients with metastatic breast cancer from Sweden and Denmark. TIMP-1 was measured using ELISA in 162 primary tumor extracts from patients who later developed metastatic breast cancer and these levels were related to the objective response to first-line chemotherapy. Increasing levels of TIMP-1 were associated with a decreasing probability of response to treatment, reaching borderline significance (OR = 1.59, 95% CI: 0.97-2.62, P = 0.07). This OR is very similar to the result from our previous study. Increasing levels of TIMP-1 were also associated with a shorter disease-free survival and overall survival, however, not statistically significant. The results from the present study support previous data that TIMP-1 is associated with objective response to chemotherapy for metastatic breast cancer.