The 50-year-old Cristina is accused of two counts of tax fraud carrying a maximum prison sentence of eight years for allegedly failing to declare taxes on personal expenses paid by a real estate company she owned with her husband.
She will sit in the dock Monday with 17 others including her husband, Olympic handball medalist turned businessman Inaki Urdangarin.
He faces more serious charges of using his Duke of Palma title to embezzle about 6 million euros (USD 6.5 million) in public contracts through the nonprofit Noos Institute he ran with an associate.