The auction, titled "Write Me and Tell Me Your Heart: Leonard Cohen's Love Letters to Marianne" by global auction house Christie's, would take place online from June 5-13.
"Postmarked from Hydra, Montreal, New York, Tel Aviv and Havana, and written during pivotal years in Cohen's career, these poetic letters brim with both biographical detail and raw emotion, documenting one of the most captivating love affairs of its time as well as the transformation of a young man into a great artist," Christie's said.
Marianne was the inspiration for the famous song "So Long, Marianne".
A highlight from the auction includes a letter written in Tel Aviv in September 1960 at the start of their relationship. Cohen writes, "It's hard to write you. The surf is too loud. The beach is too crowded, and you're too much in my heart to put anything down". It is estimated to fetch $6,000-9,000.
Also on sale is an autographed letter from February 1967 after his first major performance in New York.
Cohen describes in the letter that he "sang in New York for the first time last night, at a huge benefit concert. Every singer you've ever heard of was there performing. Judy Collin introduced me to the audience, over 3,000 people, and they seemed to know who I was, mostly because of 'Suzanne' (a song by Cohen)".
( With inputs from IANS )