Shares in Motorola have fallen 8% after the firm's latest quarterly revenues failed to meet Wall Street targets.
Motorola's latest results have disappointed
Reporting results for the three months to the end of September, Motorola said revenues rose 17% compared to the same time last year to $10.6bn (£5.7bn).
Hit by weaker-than-expected sales, the firm's performance fell below average analyst predictions of $11.06bn.
Profits at the world's second-largest mobile phone firm fell 45%, but this was due to a one-off gain last year.
Motorola's third-quarter net profit fell to $968m, or 39 cents a share, from $1.75bn, or 69 cents a share, a year ago.
When last year's one-off gain is pulled out - an investment in Nextel Communications - Motorola's profits during the third quarter of 2005 were 30 cents a share.