More than 10 million Americans travel to Mexico every year. The overwhelming majority return after having had a great experience. Caroline's answer is right, if you're on a resort you'll be fine. Just remember to follow all the usual safety rules (stuff you do at home). Don't tempt fate by walking on a secluded beach alone. Same goes for walking back to your resort or room at night.
If you want to give yourself a scare, read what the US State Dept says about travel to Mexico. just remember, because it COULD happen it doesn't mean it WILL happen.
Most people who get into trouble (anywhere in the world) have gone looking for it: buying or selling drugs, getting blind drunk, or flashing their valuable possessions. Take a sensible approach and you'll be perfectly safe. almost 10 years ago
I took my young family to Mexico including Cancun in November 2010 and we didn't stay in a resort, we stayed in the city itself, well away from the resort strip. I would say Cancun is a very safe destination. The whole economy of this city is dependent on tourism and the people of Cancun have a vested interest in making sure their city is safe for visitors. It is not necessary to be in a resort to be safe in Cancun.
As noted in the previous response, things could still go wrong, but they are most likely to do so if you don't ask yourself appropriate questions such as "Should I be walking alone on this secluded beach late at night?". Cancun is unlikely to "bite" you, but if you do something foolish or reckless, you could get "bitten" there, just as you could in your home town.
While we enjoyed Cancun, I would also suggest that there are more interesting and pleasant places to visit in that part of Mexico (Quintana Roo & Yucatan states). We loved Tulum, a quiet, low-rise and laid back beach resort and Merida, a large, dynamic and fascinating city. almost 10 years agoAnswered by peterf via Travellr.com