A new EU ruling allows businesses to legally refuse to employ smokers.
The ruling was made in response to concerns raised after an Irish company placed a job advert stating that smokers need not apply.
EU commissioner for employment, Vladimir Spidla, said that it was not an infringement of European anti-discrimination laws, which prevent discrimination on grounds such as ethnic origin, disability, age and sexual orientation.
MEP Catherine Stihler, who raised the issue, welcomed the clarification, stating that she did not think a new raft of anti-discrimination legislation was necessary.
"I was also very pleased that in the response the commission outlined their strong support for banning smoking in workplaces as a measure to protect smokers' and non-smokers' health," she said.
However, spokesman for anti-smoking group Ash told the Guardian that the ruling was "thoroughly bad public policy" and said that his organisation did not want to persecute smokers, but to help them to quit.
"Our advice to employers would be not to do that [discriminate] unless there is a clear occupational reason why smoking is not possible," he said.
Pro-smoking lobby group Forest said that it was not an employer's business whether a member of staff smoked, as long as it was done in their own time or during statutory breaks.