DNA common variants may significantly contribute to genetic risk for common diseases. Because of its biological function in DNA repair, hMSH2 gene polymorphisms are candidates for influencing cancer susceptibility and overall genetic stability. Twenty-two individuals with non-Hodgkin lymphomas (NHL) and 50 normal individuals were screened for polymorphic variants in exon 13 of the hMSH2 mismatch repair gene in order to determine if there is any association with development of lymphomas. The polymorphism screening was carried out by single strand conformation polymorphism analysis and DNA sequencing. We found a single nucleotide polymorphism: a T to C substitution at the -6 intronic splice acceptor site of exon 13 (gIVS12-6T>C). This polymorphism was present in 7.5% of normal individuals (allele frequency = 0.05) and in 22.73% of lymphomas (allele frequency = 0.11) (P<0.01). These results suggest that the polymorphism may be associated with an increased risk to develop NHL and that probably there are differences in the effect of the polymorphisms among populations.