Koirala will be accompanied by Foreign Minister Mahendra Pandey, acting Foreign Secretary Shanker Das Bairagi and Prime Minister's Foreign Affairs Advisor Dinesh Bhattarai, besides a 21-member delegation during the 10-day visit that begins on September 19.
The Prime Minister will address the 69th UNGA session in New York on September 26, according to sources.
He will also meet state heads of the SAARC countries on the sidelines of the UNGA summit.
Koirala, who returned from the US a couple of months ago after having a radio therapy for his lung cancer, will also have a medical follow up during his trip.