The former international football player and coach, lost his wife, Kate, last year after a prolonged battle with cancer.
Keshi has coached the national teams of Togo and Mali, qualifying the former to the 2006 FIFA World Cup.
In his last job with Nigeria, he won the 2013 Africa Cup of Nations and reached the Round of 16 at the 2014 FIFA World Cup in Brazil.
His family confirmed the development in a statement.
The statement was signed by his relative and manager, Emmanuel Ado.
Titled: “Stephen Keshi CON has gone to be with his wife,” the statement reads in full: “With thanksgiving to God, the Ogbuenyi Fredrick Keshi family of Illah in Oshimili North Local Government Area of Delta State, announces the death of Mr. Stephen Okechukwu Chinedu Keshi.
“Our son, brother, father, father-in-law,brother-in-law, has gone to be with his wife of 35 years (Nkem), Mrs. Kate Keshi, who passed on on the 9th December 2015.
“Since her death, Keshi has been in mourning. He came back to Nigeria to be with her. He had planned to fly back today Wednesday, before he suffered a cardiac arrest. He has found rest.
“We thank God for his life.