DR Congo president to be sworn in
Dozens of dignitaries are expected in the capital, Kinshasa, to witness Kabila take the oath of office.
Last month, the Supreme Court rejected a legal challenge by opposition leader Jean-Pierre Bemba, who claimed October's run-off vote was rigged.
The poll was intended to bring a new era of stability after years of war.
About four million people died during a five-year conflict that pitted government forces, supported by Angola, Namibia and Zimbabwe, against rebels backed by Uganda and Rwanda.
Despite a peace deal in 2002 and the formation of a transitional government a year later, the threat of civil war has remained.
On Tuesday, Ugandan military officials said at least 12,000 people from eastern DR Congo had crossed into the country to flee fighting between the Congolese army and forces loyal to dissident general Laurent Nkunda.
Kabila, 35, has been the country's head of state since January 2001, following the assassination of his father Laurent-Desire Kabila.
Last month, the Supreme Court ruled that the complaints of election fraud filed by Bemba's Movement for the Liberation of Congo party were "unfounded".
It confirmed the provisional results of the Independent Electoral Commission, with Kabila winning 58.05% of the vote compared to Bemba's 41.9%.
Bemba says he will not attend Wednesday's swearing-in ceremony.
The results showed a regional divide, with Bemba gaining most votes in the Lingala-speaking west, including Kinshasa, while Kabila won by a landslide in the Swahili-speaking east.
The polls were organized under the terms of a 2002 peace deal that drew in the armies of nine other African countries.
Under the deal, former rebels were supposed to be integrated into the army, but progress has been slow and the three former rebel leaders who are vice-presidents have retained large personal security forces.
The world's biggest peacekeeping force - about 17,000 strong - is in DR Congo to prevent unrest.