PC shipments worldwide were 92.1 million units during the fourth quarter, growing by only 2.7 percent compared to the same quarter in 2009, IDC said. IDC had originally projected growth of 5.5 percent.

The popularity of tablets like Apple's iPad has hurt the demand for PCs, said David Daoud, research director at IDC, in a statement. A new wave of tablets will hit the market this year, which could continue to hurt the PC market, Daoud said.

"Consumers are spending less than they used to," plus, devices like tablets are competing for consumer dollars, Daoud said.

Many tablets sporting Google's Android 3.0 OS, code-named Honeycomb, are expected to hit the market this year. At the Consumer Electronics Show last week, Motorola, Asustek Computer and LG showed Honeycomb tablets, while Research in Motion also showed off its PlayBook tablet, which is expected to ship by the end of the first quarter. The traditional PC powerhouses -- Hewlett-Packard, Dell, Acer and Lenovo -- are also making tablet plays to complement their PC business.

IDC in the past has said tablet shipments would be around 40 million units in 2011. Gartner has predicted tablet shipments of 54.8 million units this year.