This paper will discuss some of the current legal issues concerning passive smoking at the workplace. Employers who introduce 'No Smoking' policies must take care in the manner in which they introduce any rules and the extent to which the new rules affect those employees who have always been permitted to smoke at work. Changing the rules in an arbitrary fashion may give rise to claims for breach of contract. Smokers may also sue for constructive dismissal should the new rules be imposed in an unreasonable manner. But employers who have followed a fair procedure may have the right to discipline or finally dismiss any smoker who refuses to accept the new rules.