A single guanine insertion (1G/2G polymorphism) in the promoter of the matrix metalloproteinase (MMP-1) gene creates a binding site for the transcription factor and may affect the level of transcription of MMP-1. An elevated level of MMP-1 in cancer cells may facilitate their invasion and contribute to metastasis. To evaluate the contribution of 1G/2G polymorphism in the development and/or progression of breast cancer we genotyped 135 subjects with breast cancer. The 1G/2G polymorphism was determined by the method based on restriction endonuclease digestion. We found that the frequency of the 2G allele was higher in lymphnode-metastasis patients than in the group without metastasis (p < 0.001). We did not find differences between distribution of the genotypes and frequencies of alleles in cancer patients and in healthy subjects served as control. Our results suggest that allele 2G may be associated with lymphnode metastasis in patients with breast cancer and therefore it can be considered as a prognostic marker in this disease.