The research, which was carried out by Harris Poll on behalf of CareerBuilder in the US, found that 55 per cent of employers think that mobile phone use during office hours is preventing their staff from being as productive as they could be.
Browsing the internet for personal reasons nabbed the second place spot on the list, with 41 per cent of employers citing this, while a good old fashioned gossip came in third, with 39 per cent.
Perhaps trying to hint to their HR department that they'd prefer an open plan setup, one in ten (nine per cent) said that sitting in a cubicle was a big productivity killer in their office.
The CareerBuilder research also throws a spanner in the works for anybody hoping to trick their line manager into thinking they're just checking work emails when they're not, revealing that, although 83 per cent of workers have a smartphone, almost two-thirds (65 per cent) don't actually have their work emails set up on their phone.
When asked what it was on their phone that was just so much more interesting than the work they were supposed to be doing, 65 per cent of workers surveys admitted they'd been distracted by their personal messaging app of choice, 51 per cent said they'd been checking the weather and 44 per cent confessed they'd been reading the news.
Four per cent, whose honesty can only be appreciated, said they'd been using their phone for adult interests.
"While we need to be connected to devices for work, we're also a click away from alluring distractions from our personal lives like social media and various other apps," said Rosemary Haefner, chief human resources officer at CareerBuilder. "The connectivity conundrum isn't necessarily a bad thing, but it needs to be managed."
Employers now believe their workers are so distracted that three-quarters (75 per cent) think that at least two hours a day are being lost in productivity, while one in five (19 per cent) think their staff are productive for less than five hours of their working day.