Coote was charged back in August after an investigation by Nottinghamshire police, just months after he was sacked as a referee for comments made about former Liverpool manager Jurgen Klopp.
The 43-year-old appeared in court on Tuesday morning in relation to an allegation of being connected with a category A video, the most serious type of this kind of crime.
Despite pleading not guilty at a hearing in September, the former referee today changed his plea to guilty.
"You have pleaded guilty to a serious matter. Whether this means custody or not will be decided when all the information is before the court, which is why I have ordered a pre-sentencing report," Judge Nirmal Shant KC told the court.
After being granted conditional bail, Coote will next appear at court on December 11th for sentencing.
The charge of making an indecent image relates to acts such as downloading, sharing and saving material.