BACKGROUND: Chemotherapeutics, one of the standard treatment options for cancer worldwide, have various adverse effects, including erectile dysfunction (ED). AIM: To investigate erectile function in an animal model after administration of the anticancer agent oxaliplatin (L-OHP). METHODS: Male Wistar/ST rats were divided into 2 groups: L-OHP rats (n = 21), which were intravenously administered L-OHP (4 mg/kg; twice a week for 4 weeks), and Control rats (n = 21), which were injected with the same volume of 5% glucose solution, using the same dosing schedule. At the end of the study period, erectile function was evaluated by measuring intracavernous pressure (ICP) and mean arterial pressure (MAP) after cavernous nerve stimulation (n = 9-10). Endothelial function was evaluated with an isometric tension study using corpus cavernosum strips (n = 11). Western blot analysis was used to assess neuronal nitric oxide (nNOS) and endothelial NO synthase (eNOS) protein levels (n = 7). Real-time quantitative polymerase chain reaction (qRT-PCR) was used to assess the expression of inflammation- and oxidative stress-related markers (nicotinamide adenine dinucleotide phosphate oxidase-1, p22phox, interleukin [IL]-6, and nuclear factor-kappa B) (n = 6). Statistical significance was determined using the Student's t-test. OUTCOMES: The L-OHP group had a significantly lower ICP:MAP ratio than the control group (P < .05). Compared to the Control group, the L-OHP group exhibited significantly lower responses to ACh and eNOS protein levels and significantly higher inflammatory biomarker levels. CLINICAL TRANSLATION: The results based on this animal model indicate that use of the anticancer agent L-OHP should be considered as a risk factor for ED occurring via reduction of NO bioavailability in humans; our results provide possible treatment strategies for maintaining the erectile function of cancer survivors. STRENGTHS AND LIMITATIONS: Our study showed that the anticancer agent L-OHP has the propensity to cause ED in rats. A major limitation of this study is the lack of an established cure for ED associated with L-OHP and the lack of clinical evidence. CONCLUSIONS: L-OHP causes ED in rats via reduction of NO bioavailability caused by endothelial dysfunction. Kataoka T, Mori T, Suzuki J, et al. Oxaliplatin, an Anticancer Agent, Causes Erectile Dysfunction in Rats due to Endothelial Dysfunction. J Sex Med 2021;18:1337-1345.