Alaa and Gamal Mubarak were released from prison on Monday, one day after the fourth anniversary of the January 2011 uprising, which toppled their father after over 30 years in power, a security source told state news agency MENA.
The duo is still being retried in a corruption case. However, they were released after having already served the maximum pre-trial detention period of 18 months.
There were earlier reports that Alaa and Gamal were released on Friday.
Along with their father, they are facing a retrial on corruption charges, ordered by an appeal court earlier this month.
Their release decision overturned a lower court conviction that saw the pair given four-year jail sentences, and their father jailed for three years.
They were charged with embezzling public funds earmarked for the renovation of presidential palaces and using the money to spruce up private properties.
A Cairo court had already dropped other graft charges against the two sons in November, as well as clearing Mubarak of complicity in the killing of protesters in the 2011 uprising.