Warburg effect is a phenomenon in which cancer cells generate ATP through the glycolytic pathway despite the presence of oxygen. This leads to accumulation of lactic acid and hypoglycemia. It is a rare phenomenon but it has been described in patients with aggressive lymphoproliferative malignancies like lymphoma. We present a case of a 54-year-old male, non-hypertensive, non-diabetic, coming in for work up of intermittent epigastric pain and weight loss. Work up revealed a high grade diffuse large B-cell lymphoma with Epstein-Barr virus encoded RNAs (EBER) in situ hybridization (ISH). On the 18th hospital day, tapering of urine output was observed. Upon work up, there was an elevation of creatinine to 3.09 (1.26) mg/dL with eGFR of 23. Bicarbonate was low at 15 and also with hypoglycemia at 48 mg/dL. Arterial blood gas (ABG) revealed High anion gap metabolic acidosis secondary to lactic acidosis. He had persistent hypoglycemia despite glucose rescue doses and persistent lactic acidosis (See Figure 1). A decision was made to do initiation dialysis. He was maintained on isotonic bicarbonate drip and dialysis every other day to address the acidosis. Further plans for rituximab, cyclophosphamide, doxorubicin hydrochloride, vincristine sulfate, and prednisone (R-CHOP) chemotherapy were delayed due to pneumonia. Despite every other day dialysis, patient had persistent acidemia and had hemodynamic instability. He was appraised for continuous renal replacement therapy but given the overall prognosis, relatives decided to sign the advanced directives. He eventually expired on the 36th hospital day. In conclusion, although Type B lactic acidosis secondary to Warburg effect is a rare phenomenon, this condition should be promptly recognized among patients at risk such as those with aggressive lymphoproliferative malignancies. Early recognition is important since treatment could have an impact to the patient’s hope for survival.