The US military should be smoke-free within the next 20 years, says a government-commissioned report.
The Institute of Medicine (IOM) said 30% of army personnel are smokers, leading to "very high" economic and health costs.
But it acknowledged that the change could be hard to introduce, as smoking has "long been associated with the image of a tough, fearless warrior".
The Pentagon has said it supports the idea and believes it is "achievable".
The report, commissioned by the Pentagon and the US Veterans' Administration (VA), says the US Defense Department spends more than $1.6bn (£1bn) every year on tobacco-related medical care, hospital treatment and lost days of work.
It said that rates of tobacco smoking in the military have increased since 1998, and may be as high as 50% among service personnel returning from duty in Iraq and Afghanistan.
Soldiers who smoked were less fit, had worse night vision, and recovered more slowly from wounds.
"These troops are essentially putting their lives at risk twice: once in service to their country and once in service to tobacco," said Stuart Bondurant, chair of the report committee.
"Tobacco is a long term engagement - it kills slowly and insidiously."
The report said the armed services already "acknowledge that tobacco use impairs the readiness of military personnel and results in enormous health and financial costs".
But it criticised them for allowing smoking on military sites, giving less attention to tobacco use than alcohol abuse and for selling tobacco products to troops at reduced prices.
A spokesperson for the Pentagon said the department was in full support of the goal of a tobacco-free military.
Cynthia Smith told the AFP news agency that the goal was "achievable through the development and execution of a comprehensive plan as recommended by the IOM report".
"We look forward to using the committee's findings and recommendations as we address this challenging health and readiness issue," she said.
Source - http://news.bbc.co.uk/1/hi/world/americas/8145665.stm