The 55-year-old was stopped by police in Boughton, Chester, on 10 May.
Officers said Saunders was slurring his speech and had to prop himself up against his Audi A8 when he was asked to get out of the car.
Chester Magistrates’ Court heard that he refused to give a breath test at the roadside and again at a police station.
He pleaded not guilty at a previous hearing and was due to stand trial.
However, his lawyers indicated on Tuesday that he would not be contesting the charges and today he pleaded guilty.
Saunders, who also played for Aston Villa and Derby County and was capped by Wales 75 times, looked crestfallen when he realised he was going to jail and prison officers entered the dock.
He was also banned from driving for 30 months and ordered to pay £620 court costs.
The ex-footballer said he had been out at Chester Races and had drunk two pints.
His lawyer suggested this may have “interacted” with the medication Saunders takes for injury to his knees – and with his asthma inhaler.
Judge Nicholas Sanders told him: “Throughout these proceedings you have shown yourself to be arrogant, thinking you are someone whose previous and current role in the public eye entitles you to be above the law.
“In fact the opposite is true – someone in the public eye should expect a deterrent sentence when they flout the law.”
The Welshman, whose career as a professional footballer spanned almost two decades, later turned his hand to management at Wrexham, Doncaster Rovers, Wolves, Crawley Town and more recently at Chesterfield.
Source: Sky News