In its adverts Travelodge made a direct comparison to InterContinental Hotels Group's budget brand, Express by Holiday Inn.
The Travelodge newspaper advert said its room cost was only £39 compared with £65 for Holiday Inn.
The ASA criticised the campaign because it failed to mention that IHG's deal included breakfast, whereas the Travelodge option did not, and said the advert was "misleading" and should not be used in its current format.
A spokesman for Travelodge said: "We were happy to alter our ad following a debate with the ASA on whether a ‘complimentary' breakfast should have any relevance to a room rate as it would be free and have seemingly no monetary value.
"As the average price difference between Travelodge and Holiday Inn Express across the UK is around £26 that makes for quite an expensive breakfast," said the spokesman.
The news is the latest in a long list of increasingly aggressive marketing efforts by hotel companies to win market share.
By Gemma Sharkey
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