But only two-thirds have enforceable mobile security policies.
Mobile breaches have hit 70% of large firms around the world within the last year, according to a study from BT.
Access to mobile devices is now prevalent, with 93% of IT decision makers surveyed saying they allowed employees to use phones and tablets as part of the job, but only four in ten had bring your own device (BYOD) policies.
Mark Hughes, president of BT Security, said: "If CEOs are passionate about making security practices work, then these will inevitably become an intrinsic part of people’s lives.
"Problems usually arise when people don’t understand the risks and the impact that neglecting security could cause for the business, as well as for them personally. A security breach could cause a share price drop and reputational brand damage."
A third of mobile devices were found to have full access to internal networks or contain client information, but only two-thirds of firms had enforceable mobile security policies, which were reviewed on average every nine months.
Three in ten respondents did not have password protection on mobile devices, while only just over half of organisations had been given any computer security training.
"When people understand the repercussions of not adhering to security practices, and are given the tools to prevent them, organisations will truly be able to reap the many benefits of mobility and BYOD," Hughes added.