A 68-year-old diabetic woman was admitted to our hospital by a pneumonia diagnosed by chest radiography elsewhere. She had been on hemodialysis for the past 3 years and had no history of epilepsy or convulsive disorder. She was treated intravenously with cefepime for her pneumonia with its dose adjusted to her impaired renal function. On the 7th day of cefepime therapy, she suddenly became confused, elapsing rapidly into mental deterioration with stupor but without motor seizures. On neurologic examination, there was no neck rigidity or any focal neurological deficits except lip smacking. Laboratory test showed serum sodium level of 132 mEq/L. Brain magnetic resonance image demonstrated the finding of small vessel disease. Electroencephalogram (EEG) indicated diffuse repetitive sharp and wave complex, suggestive of non-convulsive status epilepticus (NCSE) (Figure 1A). Intravenous cefepime was discontinued and combination of valproic acid and lorazepam was given intravenously. The appearance of EEG and her mental state gradually improved following the anticonvulsant treatment (Figure 1B) and eventually she became fully alert and oriented. Impaired consciousness in uremic patients may be induced by many different etiologies, including metabolic encephalopathies, hypertensive crisis, infection, and drug toxicity as well as NCSE. NCSE is a frequently underdiagnosed but treatable cause of acute confusion or impaired consciousness and may occur during dialysis. The possible precipitating events of NCSE include alcohol, drug withdrawal, infection, hypoxia, cerebrovascular accident, menstruation, cyclosporine A therapy, malignancy, and antibiotic neurotoxicity. Especially, antibiotics such as penicillins, cephalosporins, imipenem/cilastatin, and quinolones, have been reported to cause seizure in the cases with decreased renal function. This case demonstrates that NCSE should be included in differential diagnosis of impaired consciousness in uremic patients, and emphasizes how important for a nephrologist to recognize NCSE, a potentially reversible but fatal condition if unheeded, in its early stage by promptly performing an EEG when uremic patients show acute confusion or altered mental state.