Scientists in Britain say women who give up smoking before they reach middle age will almost completely evade the risk that a tobacco-related disease will shorten their lives.
Their conclusions follow a 15 year study of 1.2 million women there. The results have been published in the Lancet.
However, the researchers warn this is not a licence for the young to smoke.
The study followed a generation of women to start smoking during the 1950s and 60s.
TheBBC reports their records showed that even those who smoked fewer than 10 cigarettes a day were more likely to die sooner.
Sir Richard Peto from Oxford University said that it was exactly the same picture as for men.