Min Bahadur Sherchan, now 78, reached the summit of the world's highest peak in May 2008, but later discovered he had lost out on the record because he failed to provide the necessary evidence of his achievement.
Instead, Guinness World Records awarded the accolade to Yuichiro Miura, a Japanese climber one year Sherchan's junior who had climbed Mount Everest in the same month.
"I am delighted to finally be recognized as the oldest man to climb Mount Everest, the highest peak in the world," Sherchan told AFP Monday.
"A younger climber was declared the record-holder last year, even though I had made the ascent in 2008. I did not know then that I had to put together the claim myself, I thought the authorities would do it for me."
Sherchan, who was to receive his Guinness certificate at a formal government ceremony later Monday, said that when he discovered his mistake he resubmitted his claim with all the necessary proof.
"I was delighted and overwhelmed when I reached the top, but I knew from the start that I would be able to do it," he said. "I did not really have much trouble with the ascent."
Sherchan summitted Everest on May 25, 2008 a day before his Japanese rival and his name will now be included in next year's edition of the Guinness Book of World Records.