Prosecutors said there was insufficient evidence against a fifth agent.
All those named will now have twenty days to reply, and any demo will probably be in absentia.
The Cambridge College scholar were exploring unbiased trade unions - a sensitive challenge in Egypt.
Italian prosecutors named the four suspects - now set to generally be charged - as Gen Tareq Sabir, Col Ather Kamal, Maj Magdi Sharif and Col Hisham Helmy.
There was no speedy response from Egypt on the Italian allegations.
Egyptian authorities have previously denied that any of their officials were being associated with Regeni's kidnap and murder. They have prompt numerous other explanations - together with that he was the victim of a robbery by a felony gang.
And on one December they said they have been "quickly closing" the investigation into the murder, Along with the killer "however 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 nine days later.
The murder triggered a diplomatic row involving The 2 nations around the world, with Italian prosecutors accusing Egyptian officers of looking to mislead the investigation.
"We have acquired unequivocal and substantial evidence," Rome chief prosecutor Michele Prestipino told a news convention on Thursday.
"For Giulio's murder There may be just gonna be a person demo, and it'll be held in Italy."
he BBC's Rome correspondent Mark Lowen suggests any demo will throw a spotlight on Egypt's dire human rights document. Egypt's Commission for Legal rights and Freedoms suggests much more check out here than two,seven-hundred individuals have been "forcibly disappeared" due to the fact 2015.
And it could prompt questions on a rapprochement with Italy's recent govt, which a short while ago accredited enormous arms income to Cairo, our correspondent states.
What happened to Giulio Regeni?
The PhD student disappeared with a investigate trip on twenty five January 2016 - the fifth anniversary of the beginning in the uprising in opposition to former President Hosni Mubarak, that means there was a major law enforcement presence in Cairo.
An Italian write-up-mortem evaluation identified that Regeni were tortured "in phases" among twenty five January plus the day of his death.
His body sustained accidents that showed he was crushed with "kicks, fists, sticks and clubs", Which he died from a damaged neck, prosecutors explained.
Egypt has denied that Regeni died in custody Though officers have admitted that safety services were being checking him.
Egyptian investigators have previously instructed that Regeni was murdered by a five-potent legal gang - and that every one of them were being then killed in the shootout. Italian officers have branded The thought "implausible".
Italian prosecutor Sergio Colaiocco told a parliamentary commission that Egyptian officers had created "faux tales... to throw see from the investigation".
Other ideas place ahead by Egyptian investigators had been that Regeni died in a vehicle incident or possibly a gay crime of passion.
His system was found on three February in a ditch through the facet of the road. His mother instructed the Italian parliament in 2018 that her son's body was so disfigured that she was only capable to go to these guys discover him via the tip of his nose.