Facebook continues to reap big rewards from ads placed on people's smartphones, which now generate more than two-thirds of its revenue.
Roughly 69 per cent of Facebook's revenue for the quarter ended December 31 came from mobile advertising, the company saidy.
Total revenue for the quarter was $US3.85 billion. That was up 49 per cent from a year earlier and beat the consensus estimate of $US3.77 billion from analysts polled by Thomson Reuters.
A year ago, mobile ads accounted for just over a half of Facebook's revenue. But as more people access the service on mobile devices, ads there have proliferated.
"We got a lot done in 2014. Our community continues to grow and we're making progress towards connecting the world," CEO Mark Zuckerberg said in a statement.
Net income for the quarter was $US701 million, a 34 per cent increase from a year earlier, while earnings per share came in at $US0.25, up $0.05.
On a pro forma basis, earnings per share was $US0.54, beating analyst estimates of $US0.48.
The company also reported a decent increase in its number of users, though the increase was greater for mobile devices. As of December 31, Facebook's monthly active users - people who log in at least once a month - were 1.39 billion, up 13 per cent. But Facebook's mobile monthly active users rose by 26 per cent, to 1.19 billion.
However, Facebook's fourth quarter costs jumped by 87 per cent to $US2.72 billion.
Revenue for the full year was $US12.47 billion, Facebook said, up nearly 60 per cent from 2013.
Shares of Facebook stock were trading at around $US74.54 in the after market hours, down by more than 2 per cent.