According to provisional data, the PDP won 30 of the 47 seats in the National Assembly, defeating its only competitor in the contest, the Bhutan Tendrel Party (BTP).
With this result, the small South Asian country will have a new government and Tshering Tobgay, who was prime minister from 2013 to 2018, will return to power.
Located between India and China, Bhutan, with a population of 770,000, has a unique two-round electoral system.
The first phase of the elections took place in November last year, in which the ruling Druk Nyamrup Tshogpa faction came fourth and was subsequently disqualified.
According to experts, the new government faces important challenges such as stimulating the country's economy.
A World Bank report found that the youth unemployment rate in Bhutan is 29 percent.
In addition, the country faces the problem of youth migration, with Australia being the main destination country.
In this regard, local reports revealed that about 15,000 Bhutanese received visas from Canberra in the 12 months to July last year, which is more than in the previous six years combined.
ode/lrd