Museveni joined other heads of state and governments at the inauguration ceremony at the Loftus Versfeld Rugby Stadium in Tshwane, Pretoria.
President Yoweri Museveni (Uganda) and Paul Kagame (Rwanda) at the ceremony
South African president-elect Cyril Ramaphosa has promised a new dawn after taking oath of office Saturday afternoon.
speaking to dignitaries at Loftus Versfeld Rugby Stadium in Tshwane, Pretoria, Ramaphosa said: "The people have spoken. We have a clear mandate. Let's get to work."
President Yoweri Museveni, who is at the ceremony, arrived in the South African city of Pretoria on Friday.
Museveni joined other heads of state and governments at the inauguration ceremony.
The Deputy Minister of International Relations and Cooperation Hon Reginah Mhawule and Uganda's High Commissioner to South Africa Barbara Nekesa received the President at Lanseria International Airport.
The Presidential inauguration theme is "Together celebrating democracy, Renewal and growth for a better South Africa".
President elect Cyril Ramaphosa 66, has taken the oath of office today after he was unanimously elected by parliament after his African National Congress (ANC) won legislative elections on May 8, winning 230 of the 400 seats.
An estimated 40 heads of state, governments, ministers and other dignitaries are in attendance.