Methemoglobinemia (MetHb), which is characterized by an increased methemoglobin level, is a rare but potentially fatal disorder caused by congenital enzyme deficiencies or exposure to oxidizing agents, including dapsone. Elevation in the methemoglobin level impairs the oxygen-carrying capacity of hemoglobin, produces functional anemia, and induces tissue hypoxia. Such hypoxia results in microcirculation injury and hypoperfusion in the tissue and organs, including the kidney, and is a risk factor for acute kidney injury (AKI). This paper reports a case of AKI caused by dapsone-induced MetHb in a patient with chronic kidney disease, in which the patient ingested approximately 1,500 mg of dapsone in a suicide attempt, which was treated with aggressive management, including methylene blue, ascorbic acid, and transfusion.