|A candidate for parliamentary elections fills in the application form as another waits for his turn in Kabul|
The three-week registration period is the first step for candidates planning to compete in September's elections.
U.N. election coordinators say nearly 10,000 candidates and more than 60 political parties are expected to participate.
Richard Atwood chairs the joint U.N.-Afghan election committee.
"We're pleased that the first morning of candidate nomination has run relatively smoothly in all 34 provinces," Mr. Atwood said.
According to the registration rules, candidates have to be Afghan citizens and provide signatures from at least 300 voters supporting their application.
People running for the national parliament also have to provide statements promising they have no links to any illegal militias.
Mr. Atwood says a number of women have already registered for the parliamentary elections. Of the 249 seats he says, 68 have been officially set aside for female candidates.
The elections are widely regarded as a key step towards full democracy for Afghanistan. Since the fall of the Taliban government in 2001, a new constitution has been adopted, followed by first ever-presidential elections last October.
Security is a key concern as the election season gets under way.
The voting was originally scheduled for last October during the presidential election, but poor organization and threats from Taliban and Al-Qaida linked rebel groups forced an 11-month delay.
Lieutenant General David Barno, commander of the U.S.-led coalition in Afghanistan, says the insurgent forces are weaker now than they were then, but the threat remains.
"I expect the enemies are looking to stage some type of high visibility attack - some spectacular media event here in the next six to nine months and, as I would put it, 'get them back on the scoreboard'," said General Barno.
U.S. and NATO military forces in the country are expected to increase their troop strength leading up to September's elections, to help guard against attacks.