The drawings, discovered by singer Marianne Faithfull's former husband John Dunbar, could be worth up to 100,000 pounds ($160,000), auction experts say.
Dunbar, speaking to the Sunday Telegraph, said he discovered the drawings inside a jotter he took on a trip to Ireland with Lennon in the sixties.
"I cannot believe it -- most of John's drawings are frightful," Dunbar told the paper.
Dunbar said they went to Ireland after spotting an advertisement offering the tiny island of Dornish Beg off the west coast for sale at just 1,000 pounds ($1,500).
He said the two had taken the drug LSD. "I had taken it first as early as 1963 whereas John had only recently started so I think he was probably more affected by it," he added.
"When we got there, John sat down and started drawing," Dunbar told the paper.
Lennon, shot dead outside his New York apartment in 1980, bought the island but eventually gave it away.