Mexico's government has estimated that 26,122 people have gone missing since December 2006, a period dominated by drug-related violence.
The latest figure is much higher than previous government estimates, which put the number at a few thousand.
The list includes more than 20,000 ongoing official investigations, but 5,206 still have to be verified.
Last week, pressure group Human Rights Watch said it found evidence "of disappearances involving state agents."
The group documented 250 disappearances that took place during the previous administration of President Felipe Calderon and accused all branches of the security forces of involvement, often at the behest of drug cartels.
The new government's estimate throws up more questions than answers, the BBC's correspondent in Mexico City, Will Grant, says.
Former members of the Calderon regime dispute the number saying there should only be around 5,000 missing.
And the current human rights official at the Interior Ministry, Lia Limon, admitted that the newly published list was only "a starting point".
"This database will be fine-tuned by the government and local prosecution services to determine in which cases the non-localisation is related to crime, as well as cases of migration, re-location for family reasons, natural disasters or others," she said.
The list covers the period between 1 December 2006, and 30 November 2012.
In many cases, the missing could simply have been immigrants who went to work in the United States without telling their family. Others could have moved to escape of drug-related violence.
The war on drug cartels declared by Mr Calderon after his election in 2006 is seen as having led to a surge in drug-related violence.
Some estimates put the number of people to have died over the past six years at as many as 70,000.
Thousands of soldiers were sent to patrol the streets, but the number of fatalities continued to rise.
Human rights groups accuse government forces of being behind hundreds of cases of missing people.
After coming into power in December 2012, President Enrique Pena Nieto has made the fight against organised crime one of his main priorities and has announced the creation of a new federal police force to help drive down murder rates.