The first groups started arriving there on Wednesday and the last ones will depart in the late hours of Thursday, before the start of the Sabbath.
The prayers, lasting two to three hours, are recited at Weisblum's tomb, after which Jews eat a kosher meal consisting of beef, fish, eggs, fruit and vegetables.
Weisblum was one of the founders of the Hassidic movement, whose aim was to revive Judaism in the 18th century. He gained a reputation as a healer of souls and bodies and wrote a treatise called Noam Elimelech, published in 1787.
Hasidic Jews believe that a person's soul returns to the place of his or her burial on the anniversary of their death.
Jews visit Elimelech's grave in Leżajsk to ask his spirit to help them with important life issues, such as health and prosperity in business and family.
Before World War II, Leżajsk had a sizeable Jewish population and was among the most important centres of the Hasidic movement in Poland. The tradition of the annual prayers at Elimelech's tomb was revived in the 1970s.
(mk/gs)