The purpose of this study was to investigate the significance of polymorphisms in the CD20 gene in patients with diffuse large B-cell lymphoma (DLBCL). We sequenced exons 3-8 in 160 patients with de novo DLBCL and detected the expression of CD20 via immunohistochemistry. We found two single nucleotide polymorphisms (SNPs): rs17155019 in the 5' untranslated region and rs2070770 (ILE72/ILE72) in exon 4. There was no significant difference in genotype frequencies of SNPs between patients and controls (p = 0.855 and 0.251, respectively). In patients who received rituximab-containing chemotherapies, the T allele of rs2070770 was significantly associated with superior overall survival (OS) (p = 0.029) and progression-free survival (p = 0.045). Analogously, in patients who did not receive rituximab, the T allele of rs2070770 (p = 0.047) was also significantly associated with longer OS. In conclusion, SNPs of CD20 were not high risk factors of DLBCL, but the T allele of rs2070770 was a potential indicator of superior survival.