Mexico’s Supreme Court has ruled that growing, possessing and smoking marijuana is legal under right of "free development of personality".
The measure approved 4-1 on the five justice panel currently only applies to the four plaintiffs in the case, who want to form a pot club, but paves the way for a change in the law.
The ruling does not make the sale or commercial production of cannabis legal or imply general legislation.
The case is the first in a series of six petitions concerning the legalisation of the drug which if all approved would set a precedent in law which allowed for future legal recreational use.
A similar process led the recent ruling that laws banning same-sex marriage were unconstitutional.
The ruling reflects the change in attitudes towards drugs in a country which has suffered decades of violence associated with the American "war on drugs", the New York Times reports.
Justice Arturo Zaldivar, who wrote the majority opinion, said: "No one has said at all that marijuana is harmless. It is a drug and, as such, it causes damage.
"What is being resolved here is that total prohibition is a disproportionate measure."
President Enrique Pena Nieto tweeted that he "respects and recognises" the ruling.
He said: "This will open up the debate over the best regulation for inhibiting drug consumption, a public health issue Mexico has promoted in international forums...broadening the discussion".
Campaigners calling for the drug’s legalisation staged a low-key demonstration outside the court building and many in the crowd celebrated by smoking when the news was announced.
Mexico is just the latest Latin American country to liberalise its drug laws.
Uruguay legalised marijuana in 2013 and Chile gathered its first harvest of medical marijuana earlier this year.
Bolivia allows the traditional use of coca - used to make cocaine - by its indigenous population and Colombian leaders have called for more liberalisation.
Additional reporting by AP
