Elim got close with his grandmother Aurora, who took care of him as an infant. His father died when Elim was just 18 years old.
He had six half-brothers and half-sisters from his father's second marriage with Princess Elena (Hélène) Petrovna Trubetskaya.
He married Countess Sophia Hilarionovna Vorontsova-Dashkova (9 August 1870, Novo Temnikovo - 16 April 1953, Athens), in Saint Petersburg on 18 April 1893. They had no children.
Speculating in 1895 about the richest man on earth, The Atlanta Journal-Constitution stated that "the wealth of Elim Demidoff is beyond calculation".[1]