The survey of 1,000 businesses showed that 87% of firms are dependent on electronic data, up from 76% two years ago.
But less than 20% back up their desktops, less than 20% store their back-ups offsite, and only 8% have tested their disaster recovery plans.
"Many businesses do not realise the value of their data until it is too late. Others think they have good back-up systems in place, but then discover they are unreliable," said Chris Potter, partner at PricewaterhouseCoopers.
The survey showed that 66% of businesses have suffered a loss of data over the past year. Roughly 50% of the firms that had a systems failure suffered major disruption to business.