He reappointed Nhlanhla Nene as finance minister, reversing his sacking by the former President Jacob Zuma.
Mr Zuma, who is facing charges of corruption, was forced to stand down earlier this month by his own party.
Mr Ramaphosa took over, promising a "new dawn" for the country and pledging to be tough on corruption.
"In making these changes, I have been conscious of the need to balance continuity and stability with the need for renewal, economic recovery and accelerated transformation," Ramaphosa said, while announcing the appointments in Pretoria on Monday night.
He kept several ministers appointed by his predecessor, but other former allies of the former president were demoted or lost their jobs.
David Mabuzza, the deputy president of the African National Congress (ANC) ruling party, was named Deputy President of South Africa.
Mr Zuma's ex-wife Nkosazana Dlamini-Zuma, who Mr Ramaphosa beat in December's ANC leadership election, was appointed minister to the presidency.
The biggest headline is his re-appointment of Nhlanhla Nene into the finance role he was fired from in December 2015. At the time the move was widely criticised, sparking panic among investors and causing the Rand to fall to record-lows against the Dollar.
He came to power after a turbulent departure by his predecessor, who resisted days of internal party pressure to resign from his post.
Mr Zuma's nine-year tenure as president was dogged by corruption allegations, while the country struggled with ballooning national debt and high levels of unemployment.
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