STORY: The march took place one week after former Attorney General Jesus Murillo was arrested for his alleged role in the disappearance of the students and its subsequent investigation.
Holding posters with photographs of the students, the protesters marched, demanding justice for their missing sons and daughters.
The arrest of Murillo on the previous Friday provided a glimmer of hope that they could find some closure, and that whoever was responsible for one of Mexico's worst human rights atrocities could finally face justice.
The country's top prosecutor at the time, Murillo oversaw the highly criticized inquiry into the incident in which 43 students from the Ayotzinapa Rural Teachers' College went missing in the southwest state of Guerrero.
For the first time last week, Mexican officials referred to the incident as a "state crime" in a report which alleged local, state and federal authorities, including the Mexican Army, were both complicit and involved in a cover-up.
Parents of the missing, like Hilda Hernandez, called for justice and asked the government to clarify the case.
"We want justice. A lot of evidence points to the fact that he (former Mexican Attorney General Jesus Murillo) obstructed (the investigation). Whether by omission or participation, he has to pay."
The arrest of Murillo is "a step," said Emiliano Navarrete, whose son is among the missing. "But we want him to talk. He has to tell the truth, he has to point to those responsible."
International experts have said Murillo's investigation, which concluded the students had been mistakenly killed by a local drug gang, was riddled with missteps and abuses, including the torture of witnesses.
Last week, a judge released nearly 100 arrest warrants related to the case.
The bodies of only three of the 43 students have ever been found.