To further explore the role of rituximab when added to the CHOP-like regimen in the treatment of immunohistochemically defined non-germinal center B-cell subtype (non-GCB) diffuse large B-cell lymphoma(DLBCL), 159 newly diagnosed DLBCL patients were studied retrospectively based on the immunohistochemical evaluation of CD10, Bcl-6, MUM-1, and Bcl-2. Altogether, 110 patients underwent the CHOP-like regimen, and rituximab was added for the other 49 patients. Cox regression analysis showed that compared with the CHOP-like regimen, the rituximab-based regimen(R-CHOP regimen) significantly decreased the risk of disease relapse and progression in CD10-negative patients (P=0.001), Bcl-6-negative patients (P=0.01), and MUM-1-positive patients (P=0.003). The risk of disease relapse in patients with non-GCB subtype (P=0.002) also decreased. In contrast, patients with the opposite immunohistochemical marker expression profile and GCB subtype did not benefit from treatment with the R-CHOP regimen. In addition, non-GCB subtype patients had a significantly higher expression rate of Bcl-2 than GCB subtype patients (P=0.042). Although univariate analysis found that both Bcl-2-positive and -negative patients had significantly higher event-free survival rates with the R-CHOP regimen, only Bcl-2 positivity (P=0.004) maintained significance in the Cox regression analysis. We conclude that the addition of rituximab can significantly improve the prognosis of patients with non-GCB subtype DLBCL, which is closely related to the expression of CD10, Bcl-6, MUM-1, and Bcl-2.