Robert Mugabe is due to be sworn in for a seventh term as Zimbabwean president.
Thursday has been declared a public holiday to allow supporters of the 89-year-old to attend the inauguration ceremony in a sports stadium in Harare.
The ceremony had been delayed by a court petition filed by his main rival, Morgan Tsvangirai, over allegations of widespread electoral fraud.
But the Constitutional Court dismissed the case, declaring Mr Mugabe's re-election "free, fair and credible".
Mr Mugabe won with 61% of the presidential vote against 34% for Mr Tsvangirai on 31 July.
The elections ended a fragile power-sharing government formed by the two men in 2009 under pressure from regional leaders following elections the year before marred by violence and allegations of rigging.
Outgoing Prime Minister and opposition leader Mr Tsvangirai said he will not be attending the inauguration ceremony.
"Expecting Tsvangirai to attend the inauguration is like expecting a victim of robbery to attend a party hosted by the robber," his spokesman, Luke Tamborinyoka, told AFP.
Mr Tsvangirai's Movement for Democratic Change (MDC) lost two court cases related to fraud claims in last month's disputed elections. Rulings were issued despite the MDC withdrawing its case saying it would not get a fair hearing.
The party alleged that more than a million voters were prevented from casting their ballots in polling stations, mostly in the capital and urban areas considered to be MDC strongholds.
The Zimbabwe Election Support Network, which placed 7,000 observers around the country, has also judged the election flawed.
But the African Union has said that any irregularities were not enough to overturn the margin of victory.
MDC officials have indicated they are unwilling to continue their partnership government with President Mugabe's Zanu-PF party.
Meanwhile, the US said recently that sanctions imposed on Mr Mugabe and some 119 other Zimbabwean individuals would remain in place until there were further political reforms.
Some 40 heads of state and government have been invited to attend the high-profile inauguration ceremony.
Once inaugurated, Mr Mugabe will serve another five-year term.
Mr Mugabe served as Zimbabwe's first post-independence prime minister between 1980 and 1987, and has held office as president ever since.