Diabetes mellitus is a growing concern in today's population and a common cause of significant morbidity and mortality in those affected. Diabetic myonecrosis is an uncommon condition that can be seen in uncontrolled, long-standing diabetic patients who complain of localized, sudden-onset muscle pain. We present a 57-year-old woman with type 2 diabetes mellitus who presented to the emergency department with left-sided pelvic pain for the past 2 months. The pain had progressively gotten worse with a significant reduction in the range of motion of her left hip. Magnetic resonance imaging imaging revealed focal enhancement, edema, and enlargement of the left iliacus muscle. Assessment of serum glucose and hemoglobin A1c revealed a history of poor diabetic control, eventually giving rise to a diagnosis of diabetic myonecrosis. She was discharged with a new diabetic regimen, pain control, and outpatient physical therapy.