The remains were found during construction work in Zapopan in Jalisco state, home to one of the country's most powerful drug cartels, prosecutor Salvador Gonzalez told a news conference.
Ground-penetrating radar and cadaver dogs were used to search for bodies following the initial discovery in February, he said.
Criminal groups in the Latin American nation often bury their victims in unmarked graves, or incinerate them to leave no trace.
Jalisco is one of the Mexican regions worst affected by a missing persons crisis that has seen more than 127,000 people vanish.
The state is a stronghold of the Jalisco New Generation Cartel, one of the drug trafficking groups classified by US President Donald Trump's administration as a terrorist organization.
Criminal violence has claimed around 480,000 lives across Mexico since 2006.
Hundreds of graves have been discovered across the country, such as in Bartolina in the northeastern state of Tamaulipas, where authorities unearthed 500 kilos of remains between 2017 and 2021, reports BSS.