The National Elections Commission announced provisional results from Friday's voting showing the governing party with 74.46% of the vote – well ahead of its nearest rivals with votes counted from nearly 60% of polling stations.
Under a new constitution introduced in 2010, an MPLA win means Dos Santos, who turned 70 this week, is elected for a further five-year term on top of the nearly 33 years he has already served as leader of Africa's number two oil producer.
Silver-haired Dos Santos is Africa's second longest serving leader after Equatorial Guinea's President Teodoro Obiang Nguema Mbasogo.
The provisional results gave the MPLA's closest challenger, former rebel group Unita, 17.94%, while the third-placed CASA-CE party had 4.53%. The turnout was just over 57%.
Further results would be announced later, National Elections Commission spokesperson Julia Ferreira said, but those in so far showed the MPLA on track for a sweeping victory in the vote, which had passed peacefully.
As they cast their ballots, many citizens called however for better power, water, health and education services and a more equal share-out of the country's oil wealth.
An oil boom fuelled rapid growth averaging 15% a year between 2002 and 2008 and prospects for national economic growth remain buoyant, but distribution of this wealth among Angola's 18-million people has been very unequal.
Thrusting new buildings and construction cranes punctuate the bayside skyline of the seaside capital Luanda, but sprawling poor slums known as "musseques" fringe the overcrowded city.
One of Angola's leading civil society activists, Elias Isaac, Angola country director for the Open Society Initiative for Southern Africa (OSISA), a pro-democracy NGO, said the results showing an easy MPLA win came as no surprise.
He criticised the fact that ballot tally sheets from the more than 10 000 polling stations across the country were not being posted publicly at the voting centres themselves but were being announced centrally by the electoral authorities.
"There is no transparency … there is no credibility in the process," Isaac told Reuters.
No immediate celebration
Opponents and civil society critics say Dos Santos has created a "one-person state" marked by rampant corruption and conspicuous enrichment of a small elite, including his family.
"The country is not going to change … we will still be in a system that is controlled by one man, there will be no checks and balances," OSISA's Isaac said.
There were few signs of immediate celebration in the streets of Luanda on a quiet Saturday, which suggested the initial results were widely expected.
It was only the third national election since Angola won independence from Portugal in 1975, and the second since the end a decade ago of a 27-year civil war in which Dos Santos' MPLA emerged victorious over Unita.
MPLA officials hailed the initial results as an indication of the ruling party's enduring support in a rapidly-growing oil producer that still bears the scars of war in damaged buildings and the mutilated limbs of landmine victims.
"These results show that the MPLA continues to be the party of the people and that we obtained a majority that will allow us to keep on growing the country in stability," MPLA spokesman Rui Falcao told Reuters.
Leaders of the opposition Unita and CASA-CE parties had bitterly criticised the vote preparations and electoral process as biased in favour of the MPLA. But despite these serious reservations, their parties had participated in the vote.
Former Cape Verdean President Pedro Pires, leading a delegation of African Union election observers, said on Friday voting appeared to have gone ahead without major problems, although some polling stations opened late.
While the initial results showed the MPLA obtaining more than 80% of the votes so far in nine of Angola's 18 provinces, the contest appeared more disputed in Luanda where the MPLA had just over 56%, against Unita with a little more than 29% and CASA-CE with nearly 12%.
The MPLA's monolithic hold on the state and its control of most local media gave it clear campaign advantages over Unita, CASA-CE and six other smaller coalitions and parties that fielded candidates.
The MPLA's dominance reflects Dos Santos' more than three decades in power during which the reserved Soviet-trained oil engineer, with military help from Cuba and the Soviet Union, survived Cold War offensives by South African apartheid forces and defeated first the FNLA and then Unita in the civil war. – Reuters