The relief shipments went to Ein Terma and Hamouria -- areas surrounded by regime forces -- as well as the difficult to reach Hazeh, Beit Sawa and Eftreis areas.
The communities are in the Kafr Batna region, which hasn't received aid since mid-April.
UN deputy spokesman Farhan Haq yesterday welcomed the news, but said "much more progress is required."
"The UN continues to call for unconditional, unimpeded and sustained access to the millions of people in besieged and hard to reach locations across Syria," he added.
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Last year, the UN sent only 34 aid deliveries, down from 50 in 2014.
Erbin and Zamalka, two of 18 besieged areas identified by the UN, have gone without potentially life-saving assistance since November 2012.
The rural Damascus suburbs in East Ghouta are controlled by rebel forces and encircled by Syrian regime troops.
The UN plans on sending humanitarian assistance via airdrops, using planes in rural areas and helicopters in densely populated regions.
Some 592,700 Syrian residents are currently living under siege, according to the United Nations.