Sales of personal computers are expected to be down 11% by the end of this year.
Research company Gartner said that falling PC sales and rising shipments of cheap tablets and mobile devices is set to continue.
Shipments of tablet computers are expected to rise by 42% and mobile phone sales will increase by 4% to more than 1.8 billion.
However Gartner says the opportunity for high-end smartphones is coming to an end, with most of the growth expected to be amongst mid and low-end devices, particularly those running Google's Android operating system.
Lower-priced tablets will also put pressure on premium devices, the company says, particularly as consumer demand for smaller tablet form factors increases.
Taking PCs, tablets and mobile phones together, Gartner predicts that there will be 2.32 billion devices shipped in 2013, a 4.5% increase on 2012.