Mexico: Citizenship by Descent

Theoretically unlimited generational transmission with no cap. However, each generation in the chain must be registered sequentially. You cannot skip generations. If a grandparent was born in Mexico but never registered their child (your parent) as Mexican, you must first register the parent before you can register yourself, even for deceased ancestors.

Since 1998, Mexican nationals by birth can NEVER be deprived of nationality through acquisition of another nationality. Renunciation must be explicit and formal; it is extremely rare.

• –Sequential registration is mandatory: This is Mexico's unique administrative challenge. You cannot go directly to "great-grandchild of a Mexican." The chain must be built link by link. Each registration requires the previous link to be established.
• –Deceased ancestors can be registered: If a grandparent never registered their children as Mexican, you can still complete the registration for the deceased grandparent's child (your parent) using birth/death certificates and genealogical documentation.
• –1998 dual nationality reform: Before 1998, Mexicans who naturalized elsewhere lost Mexican nationality. After 1998, this no longer applies; existing citizens were not affected retroactively, and going forward, no Mexican national can lose nationality by acquiring another.
• –No generational limit in law: The Constitution says "Mexicans by birth" which passes to their children, with no stated limit. In practice this means the chain can theoretically go back indefinitely.