Leeds have been fined £200,000 and given a severe reprimand by the English Football League after their investigation into spying.
The Sky Bet Championship promotion chasers had been under the spotlight after boss Marcelo Bielsa admitting to sending someone to spy on Derby.
A member of his staff was caught at the Rams' training ground ahead of their match last month, which Leeds won 2-0.
The club admitted a breach of Regulation 3.4 which states: "In all matters and transactions relating to the League, each club shall behave towards each other club and The League with the utmost good faith."
EFL chief executive Shaun Harvey said: "The sanctions imposed highlight how actions such as this cannot be condoned and act as a clear deterrent should any club seek to undertake poor conduct in the future.
"I would like to thank Leeds United for their assistance in helping to bring this matter to a conclusion as quickly as was practically possible.
"The facts of this particular case were not ones we would have expected – and have to deal with a complaint about – and it is clearly impossible to have a specific set of regulations that will apply in all circumstances of poor conduct, so, this charge was brought under a general regulation.
"In doing this, the EFL has demonstrated we have appropriate provisions in place to protect our competitions and apply to all clubs."
A new rule is also set to be introduced which will prohibit teams from viewing opposition training in the 72 hours immediately prior to a fixture, unless invited to do so.
Harvey added: "We will now look to move on from this incident and commence the discussions about introducing a specific regulation at a meeting with all clubs later this month."
Bielsa admitted Leeds had spied on all their opponents this season but remained adamant no specific rules were broken.
He also gave a detailed 70-minute briefing to the media to outline how he scouts and prepares against opposition.
It was met with a sceptical response from many rivals, including Derby boss Frank Lampard, who said such analysis was commonplace.
A statement from the Football Association read: "The FA has on this occasion decided to conclude this matter by issuing formal warnings against Leeds United FC, Leeds manager Marcelo Bielsa and a club video analyst.
"Notwithstanding The FA's decision on this occasion, The FA will take appropriate action should further evidence of this nature come to light in the future."
Having escaped a points deduction, Leeds are third in the Sky Bet Championship, two points behind leaders Norwich.
A club statement said: "We accept that whilst we have not broken any specific rule, we have fallen short of the standard expected by the EFL with regards to regulation 3.4.
"We apologise for acting in a way that has been judged culturally unacceptable in the English game and would like to thank Shaun Harvey and the EFL for the manner in which they conducted their investigations.
"Our focus can now return to matters on the field."
