Lusaka - Zambia's constitutional court on Monday threw out an attempt by the defeated presidential candidate to annul August's election results, clearing the way for President Edgar Lungu's inauguration.
Hakainde Hichilema, who lost the election by 100 000 votes, claimed that the result was rigged and launched a legal bid to stop Lungu retaining power.
Lungu took office only last year when he beat Hichilema in a snap election.
Zambia is known for its relative stability, but the run-up to the vote was marked by clashes between supporters of Lungu's Patriotic Front (PF) and Hichilema's United Party for National Development (UPND).
"There is no petition to be heard before this court," said judge Annie Sitali, ruling that a 14-day deadline for a legal challenge had expired.
Hichilema had argued for an extension after legal arguments lasted until midnight on Friday.
At the court, where hundreds of his supporters had gathered on Monday, Hichilema, known as "HH" gave no immediate reaction to the judgement.
The official results put Lungu narrowly ahead on 50.35% against 47.63% for Hichilema among a field of nine candidates, just enough to avoid a second-round run-off.
Lungu's short term in office has been marked by falling prices for copper, the country's key export, soaring unemployment and inflation rising to over 20%.