Political Constitution of Colombia (1991)

A group of citizens corresponding to one-tenth of the electoral rolls may request from the electoral organization the holding of a referendum for the repeal of a law.

This law shall be repealed if half plus one of the voters who participate in the referendum so decide as long as a quarter of the citizens making up the electoral rolls participate in said referendum.

There can be no referendum with respect to laws approving international treaties or the budget or laws relating to fiscal or tax matters.