Background: Hyperosmotic hyperglycemic nonketotic state (HHS) is associated with myriad neurological complications such as seizures. Methods: We report a case presenting with visual hallucinations due to occipital lobe epilepsy. Results: A 67-year old woman with chronic hypertension, hyperlipidemia and diabetes mellitus non-compliant to medication presented with a 10-day history of recurrent visual phenomena in the left visual field. She described stationery multi-coloured flashing lights which decreased in intensity, brightness and size after 3 minutes. She was alert and conscious during attacks. There was no limb jerking. Neurological examination was normal with no visual field defect. Capillary glucose was 28.1 mmol/L, Hba1c 9% and B-hydroxybutyrate < 0.1. She was treated with actrapid 8 units, glipizide 5 mg BD and empagliflozin 12.5 mg OM. Interictal electroencephalogram was normal with no epileptiform activity. Brain magnetic resonance imaging revealed restricted diffusion in the right occipital cortex with corresponding cortical thickening and increased FLAIR signal with subtle hypodensity on GRE sequence. Her visual symptoms improved dramatically with hydration and diabetic control. She was treated with a short course of keppra. Conclusions: Visual hallucinations are an uncommon but well recognised and fully reversible complication of HHS. Clinicians should not forget HHS in the workup of occipital lobe epilepsy.