We describe here the first case of Moraxella lacunata causing septicemia and acute tubular necrosis in an immunocompetent patient. A 34-year-old white man presented with fever, chills, and rigors for 5 days. Physical examination was significant for bibasilar lung crackles. His blood urea nitrogen and creatinine were significantly elevated at 72 and 8.7 mg/dL, respectively. His white blood cell count was 18,000/μL with 26% bands, and urine sediment showed muddy brown casts, coarse granular casts, 5 to 10 white blood cells, and 10 to 20 red blood cells. Echocardiogram was within normal limits with no evidence of endocarditis. Stool cultures grew normal enteric flora, and no ova and parasites were identified. Hepatitis serologies and autoimmune workup for renal failure were negative. A blood culture grew M. lacunata and was appropriately treated. Subsequently, renal failure resolved at the time of discharge.