Lawmakers voted to approve the constitutional amendment late Monday. Parliament amended the constitution to allow President Gnassignbe Eyadema to stay in office for essentially the rest of his life.
The constitution, adopted in the 1990s, had contained a clause that would have forced Mr. Eyadema to retire in mid 2003. It restricted him to two five year terms in office.
But the National Assembly overwhelmingly voted to lift the term limit and allow him to stay in office.
President Eyadema is already Africa's longest serving leader. He took power after a 1967 military coup, and has since been formally elected to the presidency. Amnesty International condemned the last elections, in 1998, as deeply flawed by violence that killed hundreds of people.
Opposition leader Jean-Pierre Fabre of the Union of Forces for Change party tells VOA the opposition is ready to fight against the new law and will probably call for mass demonstrations. Leaders of various opposition parties have met to plan their strategy for challenging parliament's decision.
Analysts say another change in the electoral law is aimed at excluding opposition leader Gilchrist Olympio from running for president in 2003. The newly changed law requires any presidential contender to reside in Togo for at least one year before the elections are held.
Togo's next presidential election is expected in June or July. Mr. Olympio has been living in exile for years, most recently in Paris. Under the new law, he would not be able to run for president even if he returned to his home country tomorrow.