Then, they say, a white student switched jeans with one of the black students, and the white student was allowed to enter in the same baggy pants.
In addition to the apology, managers will undergo diversity training.
The students will not file a lawsuit against the bar and they will hold a rally in Chicago late next month to address discrimination and prejudice.
One of the black students kept out says he and others have tried to use the incident to teach fellow students about race relations in America.
"There are still issues of discrimination in the united states, a lot of people a lot of people not experiencing certain situations think that we're in a post racial America and we really thought this would be a teaching moment," said Regis Murayi, Washington University student.
The U.S. Justice Department is being asked to look into the issue at the request of Missouri Congressman William Lacy Clay.