 Koirala was unmarried and known to live a simple life.A member of the politically prominent Koirala family, he was the cousin of former prime ministers Matrika Prasad Koirala, Girija Prasad Koirala and Bishweshwar Prasad Koirala.A heavy smoker, Koirala was diagnosed with tongue cancer in 2006 and lung cancer in June 2014.