Greig Thomson, 38, committed the fraud in May 2007 when he had just become a self-employed mortgage broker and adviser and was deemed too big a risk by lenders.
According to reports, Thomson used the mortgage to buy a flat in Dundee for £180,000, which he later admitted to police was done to impress a then girlfriend.
However, he was unable to maintain regular payments on it and fell into arrears.
Thomson never told his mother, Maureen, that he had used her identity to purchase the flat.
She only became aware of the fraud in 2014 when it was repossessed and sold for just £126,000.
She received a demand for the outstanding £80,000 and after questioning this, received paperwork showing her forged signature on the application.
Fearing she may have her own home repossessed, Maureen Thomson informed the police.
Hearing the case at Dundee Sherrif Court, Sherrif Alistair Brown warned Greig Thomson that he potentially faced a prison sentence for the crime.
Thomson gave up mortgage advising in 2014 and now owns digital marketing firm Outside Media Group.
Sentencing will take place on June 15.