“I went to the Iman Khomeini hospital with my daughter who needs a sonogram, but over there it costs 500,000 toman,” or roughly $200, said the woman, Zahra Hajabdolmaleki.

“We will help you here for half that amount,” Mr. Asnashahri pledged.

Named after a Jewish doctor who died in 1921 while trying to cure patients during a typhus epidemic raging through Tehran, the hospital started out as a clinic where all Iranians could come for medical care at vastly reduced rates. For more than 50 years it has been a meeting point for Iranian Jews and Muslims and the most prominent Jewish charity in the capital.

Mr. Asnashahri, who has worked at the hospital for nearly 48 years, praised the “good atmosphere” while also noting that only five Jewish physicians remained. “Many have migrated and others have bought shares in more modern hospitals,” he said.

About 96 percent of patients are Muslim, like most of the hospital’s employees. But what mattered most, he said, was the message that “here all people can come, no matter what religion, color or race.”

Though the Jewish population of Iran is dwindling — now at about 9,000, according to an official census by the Statistical Center of Iran, though other estimates range to 20,000 — the country has the largest number of Jews in the Middle East after Israel.