Many of the costs associated with prehospital care in developed countries are covered in budgets for fire suppression, police services, and the like. Determining these costs is therefore difficult. The costs and benefits of developing a prehospital care system for Kuala Lumpur, Malaysia, which now has essentially no emergency medical services (EMS) system, were estimated. Prehospital therapies that have been suggested to decrease mortality were identified. A minimal prehospital system was designed to deliver these treatments in Kuala Lumpur. The potential benefit of these therapies was calculated by using statistics from the United States corrected for demographic differences between the United States and Malaysia. Costs were extrapolated from the current operating budget of the Malaysian Red Crescent Society. Primary dysrhythmias are responsible for almost all potentially survivable cardiac arrests. A system designed to deliver a defibrillator to 85% of arrests within 6 minutes would require an estimated 48 ambulances. Kuala Lumpur has approximately 120 prehospital arrhythmic deaths per year. A 6% resuscitation rate was chosen for the denominator, resulting in seven survivors. Half of these would be expected to have significant neurological damage. Ambulances cost $53,000 (US dollars) to operate per year in Kuala Lumpur; 48 ambulances would cost a total of $2.5 million. Demographic factors and traffic problems would significantly increase the cost per patient. Other therapies, including medications, airway management, and trauma care, were discounted because both their additional cost and their benefit are small. Transport of patients (including trauma) is now performed by police or private vehicle and would probably take longer by ambulance. A prehospital system for Kuala Lumpur would cost approximately $2.5 million per year. It might save seven lives, three of which would be marred by significant neurological injury. Developing countries would do well to consider alternatives to a North American EMS model.