These Triband or Quadband Cell phones (850)/900/1800/1900MHz can be used worldwide  including USA, Canada. Mexico, Europe, Asia, South America. A very small portion of cities in USA and Canana only works with 850Mhz band and thus need a phone supporting 850Mhz. You can check  check this list to see if your mobile phone carrier in your city requires 850MHz .Just make sure at least one frequency matches the cell service frequency in your area.