Mitochondria are subcellular organelles that produce adenosine triphosphate (ATP) through oxidative phosphorylation (OXPHOS). As suggested over 70 years ago by Otto Warburg and recently confirmed with molecular techniques, alterations in respiratory activity and mitochondrial DNA (mtDNA) appear to be common features of malignant cells. Somatic mtDNA mutations have been reported in many types of cancer cells, but very few reports document the prevalence of inherited mitochondrial DNA polymorphisms in cancer patients compared to healthy control populations. Here we report the abundance of the 10398G polymorphism in a Polish breast cancer population and its frequency in controls. Amongst individuals with breast cancer the G single nucleotide polymorphism (SNP) is present in 23% of affected females compared to 3% of controls. This difference is highly statistically significant (P = 0.0008). It is therefore possible that the 10398G SNP constitutes an inherited predisposition factor for the development of breast cancer.