The British Horseracing Authority said Mahmood Al Zarooni has lodged an appeal against the severity of an eight-year suspension from training.
Al Zarooni, 37, was found guilty of administering anabolic steroids to 15 horses in his care at a BHA hearing on 25 April.
The former Godolphin handler was officially charged with rule breaches related to prohibited substances, duty to keep medication records, and conduct prejudicial to racing.
The BHA said in a statement he will now contest the length of that eight-year ban, with the date for the appeal hearing confirmed in due course.
The Dubai-born handler, who trained at Moulton Paddocks in Newmarket, has admitted to all of the breaches of the rules.
He also apologised for his actions at the hearing, at which he waived the right of legal representation.
Al Zarooni was, according to the BHA's official findings, guilty of a "widespread systematic misuse of illegal substances".
The case, widely regarded to be the most serious doping scandal in recent British racing history, led to Godolphin principal Sheikh Mohammed, who was "appalled and angered" by Al Zarooni's actions, locking down Moulton Paddocks.
Al Zarooni had until 5pm on Tuesday to state his intention to appeal.
The BHA said all of the horses which were under the care of Al Zarooni have now been tested, with the results confirmed in due course.
Al Zarooni will be represented at the hearing by William Clegg QC, instructed by Russell-Cooke Solicitors, London.