Barnes & Noble shares fell as much as six per cent, with the sliding revenue highlighting again the bookseller’s battle with giant internet rival Amazon.
The Nook sold well after its launch in 2009, but the e-reader has not kept pace with aggressively priced Kindles from Amazon, along with rival tablets from Apple and others.
Revenue in the Nook unit, including e-books and devices, fell 32.2 per cent to $109m (£67m) as the firm sold fewer and slashed prices.
The firm has lost hundreds of millions of dollars trying to compete with large tech companies.
It has said it will only make more tablets if it found a partner.
Overall revenue fell to $1.73bn in the second quarter from $1.88bn a year earlier. Net profit jumped to $13.2m from $501,000 a year earlier, after the company cut costs in the face of the falling revenue.
At book stores, sales at outlets open at least 15 months fell 4.9 per cent. Barnes & Noble said it still expects retail sales to fall by a high single digit percentage in its current financial year to April 2014.