The Co-operative Bank's workstyle survey found that 30% of those running small businesses took their work with them on holiday, while 83% regularly worked weekends.
Nearly three quarters also never took bank holidays, the report said.
The bank said that those most likely to work on holiday were people running businesses with turnovers in the £250,000 to £500,000 bracket.
Out of those who fitted that group, nearly half said they would expect to take a briefcase or laptop computer with them when they took a holiday.
Tough competition
Nearly 80% of the 302 owners, partners, directors and managing directors polled said that they felt they had to provide an "out of hours" service to their clients and customers in order to remain competitive.
The survey was commissioned by the Co-op bank's Business Direct telephone banking service.
Business Direct spokesman Ryan O'Neill said: "Everyone needs to recharge their batteries, although of course it is understandable that people building up small companies feel they have to be on call while they are on holiday."
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