Olympio has been in exile and fears for his safety
The constitutional court in Togo has rejected an appeal by the opposition leader, Gilchrist Olympio, against a ruling banning him from contesting next month's presidential election.
The court upheld the decision by the electoral commission that refused to register Mr Olympio as a candidate on the grounds that he failed to provide a current tax receipt.
The electoral law in Togo requires presidential candidates to live in the country for at least one year prior to the vote. Mr Olympio has lived in exile since 1998.
Correspondents say President Gnassingbe Eyadema - Africa's longest-serving leader after 36 years in power - is now widely expected to be re-elected.
Jean-Pierre Fabre, secretary general of Mr Olympio's Union of Forces for Change party, called the ruling "a denial of justice" .
He said the party would "mobilise the people" against the court decision.
Eyadema has been president for 36 years
Mr Olympio is the son of Togo's first president, Sylvanus Olympio, who was assassinated in 1963.
In 1992 Mr Olympio returned to the country, but his campaign motorcade came under fire which left five people in his entourage dead and 17 others including himself injured.
The opposition leader claimed he won the 1998 elections but said the results had been rigged to allow Mr Eyadema to remain in power - a view supported by many foreign observers.
Mr Eyadema, 66, dominates the political landscape in Togo and rules with an iron fist, prompting sharp criticism of his human rights record from political opponents and human rights groups.
The European Union and other western countries suspended their cooperation with Togo after disputed elections in 1993.