In some cases, victims say, the Peace Corps has ignored safety concerns and later tried to blame the women who were raped for bringing on the attacks.
"I have two daughters now and I would never ever let them join the Peace Corps," said Adrianna Ault Nolan of New York, who was raped while serving in Haiti.
She is one of six rape and sexual assault victims who agreed to tell their stories, in hopes the Peace Corps will do a better job of volunteer training and victim counseling. The report will be broadcast Friday night on 20/20.
In the most brutal attack, Jess Smochek, 29, of Pennsylvania was gang raped in Bangladesh in 2004 by a group of young men after she says Peace Corps officials in the country ignored her pleas to re-locate her.
"They all took turns raping me," she told ABC News. "They raped me with their bodies,. They raped me with foreign objects."
Smochek says the group began to stalk her and tried to kiss her and touch her from the very first day she arrived at the city where she was assigned.
"Every day we felt unsafe. And we reported everything, we just kept reporting," she said in an interview with five other former volunteers who also were rape or sexual assault victims.
She says the gang rape took place just hours after a Peace Corps safety official filed a report with the local police but again ignored her pleas for re-assignment.
She says the young men knew she had complained to the police.
"They slammed me against the wall and just started threatening me, they're calling me a filthy American whore," she said. "'We told you to stop going to the police. And now we have to kill you,'" she said.
"I was in so much pain that I just told them, 'Just kill me. Please. Just do it.'" Smochek was left unconscious in a back alley.
She says the Peace Corps immediately began to cover up what happened to her, fearful, she says, of offending officials in Bangladesh.
"When the decision was made that I was to go to Washington, D.C., I was told to tell volunteers that I was having my wisdom teeth out," Smochek says.
Peace Corps deputy director Carrie Hessler-Radelet said she was unaware of the gang rape of Jess Smochek because she was only recently appointed.
She denied the Peace Corps has attempted to cover up or keep quiet the large number of rapes and sexual assaults.
"This is the first I've heard of any report of that nature," she said.
The country director for the Peace Corps in Bangladesh at the time, Silas Kenala, told ABC News that because he no longer is a Peace Corp employee he cannot speak about the case. "All I can tell you is that I did what was required to be done according to Peace Corps procedures," Kenala told ABC News.
The Peace Corps pulled all of its volunteers out of Bangladesh in 2006, citing possible "terrorism" issues.
Between 2000 and 2009, Peace Corps figures show there were 221 rapes or attempted rapes, 147 major sexual attacks and 719 other sexual assaults—defined as unwanted or forced kissing, fondling or groping.
According to the figures, there is a yearly average of 22 rapes. There were 15 in the year for which the figures are most recently available, 2009
Peace Corps officials say the number of rapes has gradually declined over the decade.