Sprint Nextel Corp, the No. 3 U.S. mobile service, posted a quarterly loss on Thursday and said a total of 1.3 million wireless customers had left its service during the quarter.

Sprint, which has struggled with customer defections in the last few years, reported a loss of $1.6 billion, or 57 cents per share, compared with a loss of $29.3 billion, or $10.31 per share, in the same quarter a year earlier when it had a big charge.

Revenue fell to $8.4 billion from $9.8 billion a year earlier.

The company lost 1.1 million postpaid customers who pay monthly bills in the quarter, in line with average analyst expectations, according to 4 analysts contacted by Reuters. It said total wireless customers declined 1.3 million in the quarter.

Sprint expects subscriber losses to improve in 2009. It said 2009 capital spending will be consistent with 2008 levels, excluding spending on high speed wireless WiMax technology.

It expects to continue to generate positive free cash flow during 2009.

(Reporting by Sinead Carew; Editing by Derek Caney)