"Only Craigslist has the power to stop these ads before they are even published," said Kansas attorney general Steve Six in a statement Tuesday. "Sadly, they are completely unwilling to do so."
The joint letter acknowledged Craigslist faces the prospect of losing revenue if it were to remove the adult services section.
"No amount of money, however, can justify the scourge of illegal prostitution and the suffering of the women and children who will continue to be victimized, in the market and trafficking provided by Craigslist," the letter said.
The San Francisco-based Craigslist did not immediately return phone and e-mail messages Tuesday.
Some of the encounters set up through Craigslist have ended in violence and even death, authorities have said.
Last week, authorities said a former medical student accused of killing a masseuse he met through Craigslist committed suicide in the Boston jail where he was awaiting trial.
Philip Markoff, 24, was found unresponsive in his cell Aug. 15. A former Boston University student, Markoff had pleaded not guilty in the fatal shooting of Julissa Brisman of New York City and in the armed robbery of a Las Vegas woman. Both crimes happened at Boston hotels within four days in April 2009. Rhode Island prosecutors also accused him of attacking a stripper that week.
Markoff had met the women through advertisements for erotic services posted on Craigslist.
The website has put safeguards in place as it has evolved over the years.
In November 2008, after pressure from 40 state attorneys general, Craigslist required posters to provide a working phone number and pay a fee for placing an ad in the erotic services section.
In May 2009, the website renamed erotic services to adult services and said it would adopt a manual screening process, where postings would be reviewed before publishing.
But state officials believe Craigslist is still not doing enough to stop illegal ads from appearing.
Connecticut attorney general Richard Blumenthal subpoenaed Craigslist in May, asking the website to provide proof it was holding up its promise to help stop ads for prostitution.
Craigslist should provided its evidence in a few weeks, said a spokeswoman for the Connecticut attorney general's office.
Massachusetts attorney general Martha Coakley released a separate letter Tuesday that was sent to Craigslist officials and also called for the removal of adult services.
"You should continue to build on your success in connecting users to each other and providing a forum for the exchange of legal goods and services," she said Tuesday.
The 17 states whose attorneys general signed the letter are: Arkansas, Connecticut, Idaho, Illinois, Iowa, Kansas, Maryland, Michigan, Missouri, Montana, New Hampshire, Ohio, Rhode Island, South Carolina, Tennessee, Texas and Virginia.