Diffuse large B-cell lymphoma (DLBCL) is an aggressive disease influenced by genetic and environmental factors. The role of the HLA system in tumor antigen presentation could be involved in susceptibility and disease control. We analyzed the phenotypic frequencies of HLA-A, HLA-B, HLA-C, HLA-DRB1, and HLA-DQB1 in 250 DLBCLs, comparing them with 1940 healthy individuals. We also evaluated the influence of HLA polymorphisms on survival in those patients treated with curative intention using cyclophosphamide, doxorubicin, vincristine, and prednisolone (CHOP)-like regimen without (n = 64, 26%) or with (n = 153, 61%) rituximab. DLBCL patients have a higher phenotypic frequency of HLA-DRB1*01 (29% vs 19.5%, P = .0008, Pc = .0104) and a lower frequency of HLA-C*03 (6.4% vs 17.9%, P < .0005, Pc = .007) compared with healthy individuals. Irrespective of the age-adjusted International Prognostic Index, those patients receiving a CHOP-like plus rituximab regimen and carrying the HLA-B44 supertype had worse 5-year progression-free (54% vs 71%, P = .019) and 5-year overall (71% vs 92%, P = .001) survival compared with patients without this supertype. Our data suggest that some HLA polymorphisms influence the development and outcome of DLBCL, allowing the identification of an extremely good-risk prognostic subgroup. However, these results are preliminary and need to be validated in order to exclude a possible population effect.