Ratings for Celebrity Big Brother have dropped by more than half since the show began.
The launch show last Wednesday had an average of 7.1 million viewers - but by last night the audience had fallen to 3.2 million.
Channel 4 said the viewing figures were consistent with last year's series and there were no concerns about falling ratings.
But some viewers have complained that bringing Jade Goody and her family into the house has backfired.
Her arrival caused two of the show's most interesting contestants - singer Donny Tourette and filmmaker Ken Russell - to quit.
Donny scaled the Big Brother fence in protest at being told to become Jade's "servant" for the latest task.
Ken walked out after also taking umbrage with the task, informing Jade she was "slightly demented".
The ratings hit a low of 2.8 million on Saturday.
A Channel 4 spokesman said: "Saturday is traditionally a low day for ratings.
"After five days, the average for this series is 4.7 million. Last year's series average was 4.8 million so there is barely any difference.
"Ratings always go down from the launch show, it's normal for Celebrity Big Brother and regular Big Brother.
"There is still huge interest in the show and it is doing as well as the last series."