Jose Eduardo dos Santos (Angola) — 37 years

Age: 74
In power since: September 1979, when he was elected the ruling party’s leader upon the previous president’s death.
Current election rules: Under terms of a constitution approved in 2010, the leader of the party that wins a popular parliamentary vote is president for five years. Dos Santos’ party won elections in 2012, so under the new rules, he started the first of a possible two terms. The election was Angola’s third since it gained independence from Portugal in 1975, as it was often wracked by civil war.
Paul Biya (Cameroon) — 34 years

Age: 83
In power since: November 1982, when the then-prime minister succeeded a president who resigned.
Current election rules: Majority popular vote for seven-year terms. Last elected in October 2012. No term limits.
Yoweri Museveni (Uganda) — 31 years



Age: 72
In power since: January 1986, when Museveni, a guerrilla leader and former defense minister, ousted a military regime.
Current election rules: Majority popular vote for five-year terms, with no term limits. Museveni held the presidency for 10 years before he was chosen in the country’s first direct presidential election in 1996. After his re-election in 2001, Parliament removed presidential term limits in 2005. He was elected for a fifth

I hope Buhari would make the list "in Advance" as i see him leaving presidency by 2050