In 2017, the European Medicines Agency approved rituximab biosimilars (R-biosimilars) for treatment of diffuse large B-cell lymphoma (DLBCL). Thereafter, the Netherlands was one of the first countries to implement R-biosimilars, given lower costs compared with rituximab originator (R-originator). This study's objective was to investigate whether overall survival (OS) of patients with DLBCL receiving R-biosimilars is similar to patients treated with R-originator. DLBCL patients >18 years, diagnosed between 2014 and 2018, who received at least 1 cycle of rituximab combined with cyclophosphamide, doxorubicin, vincristine, and prednisolone (R-CHOP) were identified in the Netherlands Cancer Registry. Patients were categorized into R-originator or R-biosimilars groups based on data from a central repository of the Dutch medicinal drug market. The primary end point was 3-year OS, defined as the time between diagnosis and all-cause death. By the end of 2018, 91% of purchased rituximab were biosimilars. In total, 4429 patients were identified with 876 in the R-biosimilars group and 3553 in the R-originator group. Patients in the R-biosimilars group less frequently received >6 cycles of R-CHOP compared with patients treated with R-originator (24% vs 30%, P = .003). The 3-year OS did not differ between patients treated with R-originator or R-biosimilars (73% vs 73%, P = .855). This was confirmed with a multivariable Cox regression analysis accounting for sex, age, International Prognostic Index score, and number of R-CHOP cycles. In conclusion, the 3-year OS is similar for patients treated with CHOP in combination with R-originator or R-biosimilars and, therefore, favors the use of R-biosimilars in DLBCL treatment management.