The Obama Administration has yet to make clear how strongly it will enforce a federal ban on marijuana that is not affected by the Colorado and Washington votes.
"It has become necessary to analyse in depth the implications for public policy and health in our nations emerging from the state and local moves to allow the legal production, consumption and distribution of marijuana in some countries of our continent," Mexican President Felipe Calderon said after a meeting with Honduran President Porfirio Lobo, Costa Rican President Laura Chinchilla and Prime Minister Dean Barrow of Belize.
Marijuana legalisation by US states is "a paradigm change on the part of those entities in respect to the current international system", Calderon said.
Mexico has seen tens of thousands of people killed over the last six years during a militarised government campaign against drug cartels.
President-elect Enrique Pena Nieto has promised to shift Mexico's focus to preventing violence against ordinary citizens, although he says he intends to keep battling cartels and is opposed to drug legalisation. Guatemala's President has advocated the international legalisation of drugs.
Yesterday's statement by the four leaders "is an important indicator of the desire to engage in a more robust discussion of policy", said Eric Olson, associate director of the Mexico Institute at the Woodrow Wilson International Centre for Scholars in Washington.
The call by the four presidents was welcomed by marijuana activists in the US. Forcing an international review of drug policies was a stated goal of the campaigns for legalisation in Colorado and Washington.
"Marijuana prohibition in this country has been detrimental but it's been absolutely catastrophic to our southern neighbours," said Dan Riffle, an analyst lobbying for the Marijuana Policy Project, a Washington, DC-based advocacy group that largely financed the two campaigns.
Mexico is one of the primary suppliers of marijuana to the US, while Honduras and Belize are important stops on the northward passage of cocaine from South America.
Costa Rica is seeing increasing use of its territory by drug traffickers.
-AP