Jordan's Islamist factions collected 15 of 130 parliamentary seats, which marks a major victory for the Islamists who had been absent from parliament for 10 years, a local newspaper reported on Friday, citing preliminary results.
Daily independent al-Ghad newspaper cited the media spokesman of the National Coalition for Reform as saying that winning 15 seats was an "achievement" for the alliance.
The National Coalition for Reform is a list that contains the Islamic Action Front, the political arm of the Muslim Brotherhood.
The status of the other electoral lists is not clear yet.
The front competed in 2007, but boycotted the polls in the 2010 and 2013 rounds, arguing the electoral system was unfair.
On Tuesday, just under 1.5 million Jordanians cast their ballots in the country's 18th round of parliamentary polls, the first contested by most opposition groups under a new electoral law.
Some 4 million Jordanians above the age of 17 were eligible to vote, meaning turnout was just 37 per cent.
Previously, voters could only cast one vote for one candidate. This time they voted for a list then for multiple candidates within that list.
The elections this year came amid regional turmoil. The ongoing civil war in neighbouring Syria has taken its toll on the country's economy as the mostly desert kingdom hosts almost 1.5 million Syrian refugees.