The province's conflict of interest commissioner released a report this week saying Graham was in a conflict of interest when his Liberal government gave a $50 million loan guarantee to a construction company.
Patrick Ryan said Graham should have removed himself from cabinet discussions in March 2009 over the loan guarantee to Atcon because his father was a paid consultant of Atcon companies.
Graham said the conflict was an oversight on his part and he accepts full responsibility for his actions.
Graham was elected premier in 2006 but ousted from power four years later.
He says he will continue to serve as the member for the riding of Kent until March 11.
