The complainant said the ads did not clarify that new customers had to part with £900 of their own money before they could claim the £200 of free bets stated in the offer.
Bet365 Group said the ads stated the offer was subject to terms and conditions.
It said the the terms were too complex to be included in the ads but they were available on its website.
It felt the magazine’s readership were an educated betting audience and would automatically understand the terms of the free bets.
The ASA noted that consumers were required to spend £900 of their own money to obtain the full £200 of free bets, with a minimum spend of £25 to receive a bet worth £25.
It considered these significant conditions were likely to influence consumers’ understanding of the offer and because the information had not been included in the ads they were likely to mislead.
The ads must not appear again in their current form.