The incident allegedly happened in October 2011 at a Hilton hotel in Lisle.
In the lawsuit, the woman claims the bartender, Jayson Dabrowski, put a drug in her drink, got the key to her room from the front desk, then raped her.
Her lawyer says he received a copy of the police report where Dabrowski claims their sexual encounter was consensual.
The suit alleges front desk personnel made no effort to find out why he needed the key.
"The next thing she remembers is a guy in her room in a sweatshirt, between her legs, pants coming off, and she wakes up in the morning and has a very uncomfortable feeling like she didn't understand what happened," said her attorney, Jeff Deutschman.
Dabrowski is charged with misdemeanor trespassing and he has been fired from his job.
The hotel's general manager told ABC 7 News that "for over 30 years, our number one priority has been guest security and safety. These allegations are completely false."