Thorntons has endured a difficult time recently and is currently undergoing a strategic review, which will lead to the closure of 180 stores over three years.
In a frankly worded statement, the company said it "now considers profits for its full year will fall short of current expectations".
It said its pre-tax profit figure will be around break-even for the 53 weeks ending June 30 next year but this figure excludes "onerous" lease charges.
Thorntons' profits have been hit by supermarkets offering big discounts on chocolate sales.
The company has issued a number of profit warnings this year.
In August it attempted to rejuvenate its brand through ecommerce, driving awareness of its online business, and pushing the "convenience" of its offers and gift-delivery service.
In September, the company reported a loss of £253,000 for the year to 25 June. This compared to a profit of £4.4 the year before.
HMV and Blacks Leisure are among other high-street retailers which have endured difficult trading of late.
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