ROME, March 12— Visiting his boyhood home in Wadowice, Poland, last summer, Pope John Paul II nostalgically pointed out to followers the house where he grew up. Explaining that it had belonged to a Jewish landlord, the pope said: ''I don't know what happened to him. I think he died.'' The pope went on to explain that many Jews in Wadowice ''were killed in ghettos and then in camps.''

On Friday, the 79-year-old pope had a private audience with Ron Balamuth, a New York psychiatrist and the grandson of Yechiel Balamuth, who rented rooms to Karol Wojtyla and his father before World War II, and who died in a concentration camp in Poland.

Mr. Balamuth, whose father survived the Holocaust and moved to Israel, has been struggling for years to regain his family's title to the house, now a papal museum.

When the pope mentioned Mr. Balamuth's grandfather in Poland last June, the case became public, but Mr. Balamuth has yet to formally regain title to the house.

He said he wants a plaque placed at its door, explaining that it was both the home of the pope and the property of the Balamuths, most of whom died in concentration camps. ''There has not been much movement,'' Mr. Balamuth said of his efforts to persuade Polish officials.

Before last summer, Mr. Balamuth had written to the Vatican, seeking the pope's support, but had received letters from Vatican officials redirecting him to local officials in Poland. He renewed his efforts after the pope's public mention of his grandfather.

Reached today, Stanislaw Kotarba, a member of Wadowice's city council, said he had received Mr. Balamuth's proposed text for a plaque and deemed it ''very good.'' He said it might be attached to the house next month.

The meeting at the Vatican on Friday, arranged by Aharon Lopez, the Israeli ambassador to the Holy See, and Jerzy Kluger, a Jewish boyhood friend of the pope who survived the war and lives in Rome, did not deal with Mr. Balamuth's legal claims. Instead, Mr. Balamuth said he requested the meeting to cull the pope's memories of his relatives. Mr. Balamuth said the pope lit up when he showed him an old photograph of the storefront beneath the house, and said he pointed out the local church.

''I asked him about my father, who died in 1969, whether he got into mischief,'' Mr. Balamuth recalled. ''He looked at me and said, 'No, he was a good boy.' He was almost reproachful, as if saying, 'Don't be disrespectful to your parents.' ''

Mr. Balamuth said the pope stood and held his hand throughout their 15-minute discussion.

''That was very moving,'' he said. He said he was struck by the pope's fragility, and also his determination to keep working. ''When you see him close up,'' Mr. Balamuth said, ''he is so single-mindedly focused on what he seeks to accomplish.''

Photo: Ron Balamuth, a New York psychiatrist, and his wife, Limor Kaufman, showed pictures of his grandparents to Pope John Paul II on Friday. (The Vatican via Ron Balamuth)