The Swedish telecom group reported a net profit of 314mn Swedish kronor (£26.9mn) for the period, compared to 3.89bn kronor in fourth quarter of 2008. Sales revenue fell by 13 per cent to 58.3bn kroners,
The results were much worse than analysts' forecast. The company blamed the poor show on a slow transition of customers from telephone to broadband.
The world's biggest mobile networks maker is going to cut 6,500 jobs, 1500 more that what it had announced last year, as part of a restructuring programme aimed at reducing costs.
Ericsson president Hans Vestberg said that in the second half of 2009, networks' sales were impacted because mobile operator cut back on spending in a number of markets.
He added that group sales for the full year were less affected and the operating margin increased slightly.
Ericsson shares fell around 3 percent after it posted its Q4 sales figures.