Smokers in a north-east London borough will not be able to foster children from January 2010 - unless there are "exceptional circumstances".
The ban was passed on Tuesday evening by Redbridge councillors who voted unanimously in favour of the policy.
Redbridge Council wants to protect children from "the damaging effects of passive and second-hand smoke".
But the Fostering Network said it was concerned the policy could prevent good people from becoming foster parents.
Cabinet member for children, Tory councillor, Michael Stark, said: "We know this is a difficult issue because some people will feel it is an intrusion on personal freedoms, but we also know that smoking increases the risk of serious illness in childhood."
The risk of cot death, asthma, middle ear disease, pneumonia and bronchitis is also said to be higher if children live in a home where people smoke.
All new applicants to the foster care programme will be told at an early stage that they will not be able to foster if they smoke, unless there are "exceptional circumstances", the council said.
Existing foster carers who smoke will be given help to give up.
A spokesperson for the smokers' rights group Forest: "This is another attempt to stigmatise smokers and separate them from the rest of society.
"This discriminates against plenty of people who would have made excellent foster carers, and so it is damaging not only for them but also for the children that they would have fostered."
(BBC)
I am not sure if I'd approve of this ban. What about the alcoholics? Does any ban alcoholics from fostering kids? They're much worse than smokers.