Almost three in four workers lose more than three hours every weekend worrying about work, a survey suggests.
A study of 2,000 British adults, conducted by Populus, showed the biggest worriers were aged between 25 and 34 and lost more than four hours a weekend worrying.
Employees in London are the most likely across Britain to have work stresses affect their weekend.
Sunday night blues hit 53% of workers who worried on the eve of the working week - but surprisingly a relatively high 13% also worried about their jobs on a Friday night.
The most common causes of work worry are concerns about job security and the threat of redundancy.
More than one in five employees worry they are not fulfilling their potential at work.
The research was carried out for the employment group Engage for Success.
David MacLeod and Nita Clarke of the group said: "Many people are experiencing real concern about job security, which is understandable in the current climate, but in almost equal numbers, British employees are worried they aren't realising their full potential or that their manager doesn't recognise their talents.
"Unrealised talent and lack of recognition are things that are possible to change, and for that reason it is not acceptable for so many people to be affected in this way.
"It may not be realistic to think we can eliminate the Sunday night blues completely, but improved engagement in the UK has potentially huge benefits for both employees and their organisations in terms of improved wellbeing, productivity and innovation."