Introduction: Unhealthy use of alcohol can be associated with serious adverse events. Patients with alcoholism and malnutrition are at high risk for electrolyte disturbances, commonly hypokalemia. Here in we describe a case of alcohol use disorder presented with weakness and subsequently developed cardiac arrest secondary to severe hypokalemia. Case description: A 51-year-old lady presented to our emergency department because of generalized body ache and marked weakness in both lower extremities for two days duration. She had a long-term history of alcoholism, consuming two to three pints of vodka every day for about 20 years. Her last drink of alcohol was about 48 hours prior to presentation. Her examination revealed bilateral lower limb weakness of 4/5, with intact sensory system and reflexes. Biochemical analysis of the serum showed severe electrolytes disturbance, a potassium level of 2.3 mmol/L (reference 3.6-5.1 mmol/L). Electrocardiogram (ECG) showed no arrhythmias, but changes characteristic of hypokalemia with marked corrected QT segment prolongation (QTc 551ms). Aggressive supplementation of electrolytes was initiated, however, potassium level failed to increase and subsequently she had a sinus bradycardia followed by cardiac arrest. Cardiopulmonary resuscitation was initiated, return of spontaneous circulation was obtained. During the following days, potassium supplementation was continued to achieve normal plasma potassium level. She was then discharged from the hospital with recommendations for abstinence from alcohol. Conclusion: Patients with chronic alcohol-use can have serious electrolyte disturbances including hypokalemia which can have life-threatening consequences. Prolonged potassium supplementation over several days is required to achieve normal level of plasma potassium and replenish total-body potassium deficit.