Thursday's measure was included in a $1.4 trillion spending package that passed the House of Representatives earlier this week and prevailed 71-21 in the Senate with support from both Republicans and Democrats, reports Efe news.
President Donald Trump is expected to sign the bill into law.
The federal legislation follows action by 19 states and the District of Columbia to stop the sale of tobacco to people under 21.
The Senate majority leader, Kentucky Republican Mitch McConnell, began advocating for the measure in April, citing the need to discourage teenagers from vaping.
Concerns about vaping have grown this year amid 54 vaping-related deaths, but what has become known as the 'Tobacco 21' movement is equally worried about traditional tobacco products.
Last month, Trump offered support for the idea of raising the vaping age to 21.
In October, the President said that he ordered the US Food and Drug Administration (FDA) to take steps to remove all but tobacco-flavoured e-cigarettes from the market to make vaping less appealing to teens.
Trump subsequently reversed course in the face of opposition to the ban from some conservative organisations and industry groups.
The FDA imposed regulations on vaping in 2016, prohibiting the sale of e-cigarettes to people under 18.
A significant number of tobacco companies, including Juul, the market leader in e-cigarettes, supported the bill passed by Congress this week, apparently hoping to ward off stricter measures such as a complete ban on flavoured e-cigarettes.
But Senator Dick Durbin indicated that he would continue to press for such a ban.
"Any serious solution to skyrocketing rates of youth e-cigarette use must include the removal of kid-friendly flavours, not just the tobacco industry's preferred policy," the Illinois Democrat said in a statement.
( With inputs from IANS )