Nearly one in five American women have been sexually assaulted at some point in their lives, says report.
Releasing the results of a first-ever survey of nearly 10,000 women contacted randomly by telephone in 2010, the federal agency said 18.3 percent of women "have been raped at some time in their lives."
That includes "completed forced penetration, attempted forced penetration, or alcohol/drug facilitated completed penetration," it added in an executive summary of the 113-page report posted on its website.
Just over half of female rape victims (51.1 percent) said they had been targeted by an "intimate partner" -- a current or former partner or spouse -- and 40.8 percent by an acquaintance.
It also found that 1.3 million women had been raped during the year preceding the survey -- a substantially higher number than the 188,380 rapes and sexual assaults cited in a Department of Justice crime survey for 2010.
And it revealed that 24.3 percent of women -- and nearly one in seven men -- have suffered "severe physical violence" at the hands of an intimate partner, such as being hit, slammed against a surface, or beaten.
"This landmark report paints a clear picture of the devastating impact these violent acts have on the lives of millions of Americans," Health Secretary Kathleen Sebelius said.
In a statement, she said the findings of the ongoing National Intimate Partner and Sexual Violence Survey would help the administration of President Barack Obama shape policy to combat domestic violence and sexual abuse.
Scott Berkowitz, president of the Rape, Abuse and Incest National Network, or RAINN, the nation's biggest anti-sexual violence group, said the data on the lifetime risk of rape was "pretty close" to levels seen in previous studies.
But he added that "it's hard to know what to make" of the yawning difference in the number of rapes in the CDC report and the Department of Justice survey, which is based on a substantially bigger number of respondents.
"We really need to look into this more," he told AFP. "But overall, it shows what crime statistics have shown for years -- that this is an enormously violent crime that affects nearly every family in America."
The report also touched upon male rape, finding that one in 71 men -- nearly five percent of all American men -- had been raped in their lifetime, based on responses from more than 7,400 men who participated in the survey.
More than a quarter of them, or 27.8 percent, said they had been raped before they were 10 years old.
The report called sexual and intimate-partner violence a major public health concern, with survivors liable to face everything from actual physical injury to mental illness and gynecological or pregnancy complications.
"These consequences can lead to hospitalization, disability or death," it said.