The national emergency number in Mexico is 911. That number will connect you to police, medical services, and the fire brigade.
In order to be prepared for an emergency in Mexico, acquaint yourself with the medical facilities near you and keep their contact information at hand. Private insurance companies have their own emergency contact numbers that they will provide to their policyholders. You should know what hospitals your insurance covers, as well as possible procedures that may be excluded from your plan.
Make sure you’re always carrying some sort of identification and that you have an emergency contact, as well as your insurance information. Many hospitals will not admit you even in the emergency room unless you have insurance or a no-limit credit card. Even so, depending on your emergency, the nearest hospital might not be the best option - if you have time to reach a better one, do so.
The emergency number for police, medical services, and the fire department is the same: 911. Easy to remember, but keep it written down somewhere just in case.