Pier Giorgio Frassati was the son of
Adelaide Ametis, a very gifted painter, and
Alfredo Frassati, an influential journalist and politician. He had one younger sister
Luciana.
A fact not commonly known is that the Frassatis lost a child before Pier Giorgio was born. Their daughter Elda died in infancy at the age of eight months.
Pier Giorgio was very close to his aunt Elena Ametis as she lived with them and helped to manage their household for many years. Mrs. Frassati had another sister Emilia who died of an apparent heart attack at just 20 years old. Mr. Frassati had two sisters, Emma and Giulietta, and one brother, Pietro. Like his wife, he suffered the tragic loss of a sister at a young age when Emma was killed by her fiancé. A kindergarten in Pollone was named in her memory.
Pier Giorgio's maternal grandparents were Francesco and Linda Ametis. His paternal grandparents were Pietro and Giuseppina (Josephine) Frassati.