Introduction: Metformin-associated lactic acidosis is a rare, yet fatal condition, especially in the presence of risk factors. Therapeutic use of metformin may induce lactic acidosis. Gastrointestinal bleeding, dehydration, acute renal failure, and drugs are major risk factors that increase the mortality risk associated with metformin-associated lactic acidosis. In this regard, this case study aimed to present a patient, who died due to metformin-associated lactic acidosis despite treatment. Method: This case study featured a 45-year-old diabetic patient with metformin use, who presented to the emergency department with the complaint of low back pain. He had acute renal failure, severe lactic acidosis, and shock findings. Discussion: The primary purpose of metformin-associated lactic acidosis treatment is to restore acid-base balance and provide hemodynamic support. Hemodialysis reduces the mortality due to metformin-associated lactic acidosis by decreasing lactate clearance. Supportive therapies should be used. Nevertheless, mortality still occurs in approximately 50% of the cases. Conclusion: Metformin overdose or even therapeutic levels of metformin use can cause MALA in the presence of various risk factors. MALA, a rare clinical condition, is associated with mortality rates of up to 50%. The most crucial step in treating MALA is hemodialysis/venous hemofiltration. Given that metformin is a frequently used medication, care should be taken in the follow-up of patients using metformin, considering MALA.