Hyperlactemia is defined as whole blood lactate levels > 2 mmol/L. Type-B lactic acidosis refers to conditions wherein overproduction of lactate is not related to reduction in tissue oxygen. The occurrence of severe lactic acidosis in malignancies is a rare and often pre-terminal complication. We present two HIV positive patients with type-B lactic acidosis as a pre-terminal event after being diagnosed with non –Hodgkins’ lymphoma. The first patient, a 45-year-old male, HIV positive since 2012 on therapy admitted with h/o of pedal edema, generalized weakness and decreased appetite 1 week duration. Abdominal ultrasound scan revealed bilateral moderate hydro-ureteronephrosis with large left pleural effusion, cytology revealed malignant serous lymphoma confirmed by supraclavicular lymph node biopsy. Before initiation of chemotherapy, his general condition rapidly worsened with onset of lactic acidosis (10 mmol/L) and he expired. The second patient, a 59-year-old male presented with acute hematemesis. He was detected to be HIV positive 2 months earlier and was on anti-retroviral therapy. Evaluation revealed a diagnosis of diffuse B large cell lymphoma extending from gastric fundus to pylorus. CT abdomen showed diffuse and extensive disease in the stomach with splenic, peritoneal, lung metastasis and diffuse intraabdominal lymphadenopathy. He was started on chemotherapy two days later, he had a massive hematemesis with deterioration in clinical condition, severe metabolic acidosis and hyperlactemia of 19 mmol/L. Patient expired despite bicarbonate infusion, high dose thiamine and hemodialysis. Type-B lactic acidosis is a rare event in hematological malignancies and often is a poor prognostic factor determining survival.