Colorectal cancer patients have increased plasma levels of tissue inhibitor of metalloproteinases-1 (TIMP-1). However, it remains unresolved whether colorectal adenomas are associated with increased plasma TIMP-1. Plasma TIMP-1 levels were determined using an immunoassay in 121 patients prospectively enrolled from surveillance colonoscopy programmes. TIMP-1 levels were correlated to various clinicopathological parameters. No significant associations were found between plasma TIMP-1 and size, macro- or microscopic morphology or grade of dysplasia of the adenomas. No significant differences in TIMP-1 levels were found between patients with adenomas (n = 36), hyperplastic polyps (n = 12) or no pathology (n = 68) of the large intestine. However, patients with colonic (n = 3) or rectal (n = 2) adenocarcinomas had significantly increased TIMP-1 levels (P = 0.02). The present study demonstrates that measurement of plasma TIMP-1 cannot be used for the identification of adenomatous or hyperplastic polyps of the large intestine.