If a Mexican Citizen marries a Canadian Citizen in Canada does the Mexican Citizen automatically have Canadian Citizenship?

Not automatically, no. Any foreign national CAN become a US citizen, but, request has to be made. In many cases, Dual Citizenship may be offered by the original nation, and may or may not be considered by the US INS. Please make careful inquiry of BOTH the original nation and the US INS to avoid any problems. _____________________________________________________________________ yes, even if you werent canadian.