Prosecutors said there was insufficient evidence versus a fifth agent.
Those people named will now have twenty times to respond, and any demo will most likely be in absentia.
The Cambridge University college student had been studying independent trade unions - a sensitive difficulty in Egypt.
Italian prosecutors named the 4 suspects - now established to be charged - as Gen Tareq Sabir, Col Ather Kamal, Maj Magdi Sharif and Col Hisham Helmy.
There was no immediate reaction from Egypt for the Italian allegations.
Egyptian authorities have previously denied that any of their officials had been associated with Regeni's kidnap and murder. They have got advised different other explanations - which includes that he was the target of a theft by a felony gang.
And on 1 December they mentioned they were "briefly closing" the investigation to the murder, Together with the killer "even now unknown".
Regeni went missing in Cairo in January 2016 and his mutilated and naked human body was located in a ditch in the vicinity of Cairo 9 times afterwards.
The murder prompted a diplomatic row between The 2 nations, with Italian prosecutors accusing Egyptian officials of attempting to mislead the investigation.
"We now have acquired unequivocal and considerable proof," Rome Main prosecutor Michele Prestipino advised a news conference on Thursday.
"For Giulio's murder You can find just likely to be one particular trial, and it'll be held in Italy."
he BBC's Rome correspondent Mark Lowen suggests any demo will toss a Highlight on Egypt's dire human legal rights history. Egypt's Fee for Rights and Freedoms says over 2,700 folks have been "forcibly disappeared" given that 2015.
And it could prompt questions about a rapprochement with Italy's present government, which recently approved substantial arms income to Cairo, our correspondent states.
What transpired to Giulio Regeni?
The PhD student disappeared with a study journey on twenty five January 2016 - the fifth anniversary of the start of the uprising in opposition to previous President Hosni Mubarak, meaning there was a significant police presence in Cairo.
An Italian publish-mortem assessment discovered that Regeni were tortured "in phases" between 25 January along with the working day of his Demise.
His body sustained accidents that confirmed he was overwhelmed with "kicks, fists, sticks and golf equipment", Which he died description from a damaged neck, prosecutors explained.
Egypt has denied that Regeni died in custody While officials have admitted that stability providers have been checking him.
Egyptian investigators have previously advised that Regeni was check out here murdered by a five-strong prison gang - and that all of them have been then killed inside a shootout. Italian officials have branded The theory "implausible".
Italian prosecutor Sergio Colaiocco explained to a parliamentary commission that Egyptian officials experienced established "phony tales... to toss from the investigation".
Other strategies put ahead by Egyptian investigators were that Regeni died in an auto accident or even a gay crime of passion.
His human body was discovered on 3 February in the ditch with the facet of a street. His mom advised the Italian parliament in 2018 that her son's body was so disfigured that she was only in a position to establish him with the tip of his nose.