The BBC has unveiled a code of conduct for its competitions on television, radio and online services.
Blue Peter was fined £50,000 for falsifying a competition
It follows recent incidents in which the corporation admitted it had misled viewers and listeners, including one involving a contest on Blue Peter.
The code says every entry to a contest "should have a fair chance of winning" and that winners should be "genuine".
Director general Mark Thompson told staff that competitions would be phased back in by the end of the year.
The BBC suspended all phone-in competitions in July after an internal inquiry found serious editorial breaches in six shows, including Comic Relief and Children In Need.
'Honest, fair and legal'
Also in July, media watchdog Ofcom fined the corporation £50,000 after children's programme Blue Peter falsified the results of a competition during a live show.
The new code says competitions should be "conducted in a way that is honest, open, fair and legal". It also states: "Whatever pressures there may be to 'keep the show on the air', the BBC must never compromise its editorial integrity.
"If things go wrong with running a competition or vote we will not cover it up or falsify the outcome."
Mr Thompson added: "Trust is the BBC's most important value and we must never do anything that may undermine that trust. That belief is shared by the BBC's programme makers.
"The new code will enable audiences to have a clear understanding of what they should expect in the conduct of competitions and votes on the BBC.
"Audiences enjoy interacting with BBC programmes and output. It's important that they can do so with confidence at all times."