The medical examiner's office says San Francisco Mayor Ed Lee died of a heart attack.
Mayor's office spokeswoman Deirdre Hussey confirmed the official cause of death for the mayor. He died last week after collapsing at a Safeway supermarket near his home.
The 65-year-old Lee served as the city's first Asian American mayor and presided over a period of great change in San Francisco, as it climbed out of recession and into rapid economic growth.
Lee was remembered Sunday for his humility, integrity and infectious smile during a public celebration of his life at City Hall, attended by family members, former staff, politicians and residents.
Edwin Mah Lee was born May 5, 1952, in Seattle to immigrants from Toisan, a rural village in China's Guangdong province.