The US Senate has approved a ban on so-called "partial birth" abortion and sent the bill to President George W Bus, who said he would sign it into law.
The 64-34 vote pleased anti-abortion groups but pro-abortion rights groups were poised to sue to get the legislation declared unconstitutional.
Under the bill, a doctor could face up to two years in prison as well as civil lawsuits for performing a "partial birth" abortion, defined as intentionally killing a fetus that has been partially delivered. Sponsors say it entails sticking a scissors or other sharp object into the base of the skull.
If it withstands legal challenges, the ban would constitute the first federal limit on a type of abortion since the 1973 Roe versus Wade Supreme Court ruling backing abortion rights.
The National Right to Life Committee said Congress was "inviting the Supreme Court to re-examine that extreme and inhumane" 1973 decision.
"This is very important legislation that will end an abhorrent practice and continue to build a culture of life in America. I look forward to signing it into law," Bush said in a statement issued in Singapore.
The American Civil Liberties Union, Planned Parenthood, and other abortion rights groups have pledged to file lawsuits, in part because the bill has no health exemption.
Sponsors of the bill said they drafted it to specifically address one "gruesome" procedure that is performed most often in the fifth or sixth month of pregnancy.