Ifosfamide (IFO) is an antineoplastic drug that is commonly used to treat gynecological and breast cancers. Hemorrhagic cystitis (HC) is a common side effect associated with IFO injection, which courses with neutrophil accumulation and affects 6–50% of patients depending on dose intensity. Here, we investigated the role of neutrophils in this inflammatory process. Female Swiss mice (n = 8/group) were injected with saline, IFO (400 mg/kg, i.p.), fucoidan (a P- and L-selectins inhibitor, 100 mg/kg, i.v.) or IFO + fucoidan (1–100 mg/kg) alone or combined with mesna (80 mg/kg i.p.). Another group of mice received anti-Ly6G antibody (500 μg/mouse, once daily for 2 days) for neutrophil depletion before IFO injection. In another experimental setting, animals received granulocyte colony-stimulating factor (G-CSF, 400 μg/kg), IFO (200 mg/kg), G-CSF (25–400 μg/kg, for 5 days) + IFO (200 mg/kg, i.p.) or fucoidan + G-CSF + IFO. Bladder injury was evaluated 12 h after IFO injection. IFO 400 mg/kg significantly increased visceral hyperalgesia, bladder edema, hemorrhage, vascular permeability, MPO, IL-1β and IL-6 tissue levels, and COX-2 immunostaining and expression versus the saline group (P < 0.05). Conversely, fucoidan (100 mg/kg) significantly attenuated these parameters compared to IFO-injected mice (P < 0.05). Additionally, fucoidan potentiated mesna protective effect when compared with IFO + mesna group (P < 0.05). Accordingly, neutrophil depletion with anti-Ly6G reduced inflammatory parameters and bladder injury compared to IFO (P < 0.05). In contrast, G-CSF enhanced IFO (200 mg/kg)-induced HC, which was significantly attenuated by treatment with fucoidan (P < 0.05). Therefore, neutrophils contribute to the pathogenesis of HC.