The number of smokers turning to the NHS for help to kick the habit has trebled in the last decade, data shows.
But despite nearly 788,000 using the services in England this year, fewer than half succeed, figures from the NHS Information Centre reveal.
And many of those who do quit - 384,000 in 2010/11 - later relapse.
This means a fifth of adults in England are smokers, even though more are using quit smoking services at a cost of £84.3m in 2010/11.
This is nearly half a million pounds more than in the previous year and almost £60m more than t10 years ago.
Experts said the figures suggest that while there is a greater resolve within society to quit smoking, over half of all attempts fail.
NHS Information Centre chief executive Tim Straughan said: "NHS Stop Smoking Services in England saw more quit dates set with it in the last financial year than ever before; and indeed the greatest ever number of successful quit attempts.
"But while a bigger number of quit dates are being set with the service and the number of attempts to successfully kick the habit have also risen, overall the success rate is hovering at just below half."
Martin Dockrell, Director of Policy and Research at Action on Smoking and Health, said: "This shows how much people want to quit and yet how hard it can be. The Stop Smoking Services provide the best chance of success in helping a person to stop smoking. Few smokers will manage to quit first time so it is encouraging that a greater number of smokers are getting the best available help."
A spokesman for the Department of Health said smoking was one of the biggest challenges in public health.