كتب : Sherif Tarek
The 27-year-old, whose contract with Middlesbrough was recently terminated, inked a year-long deal with the Dutch side, where he plied his trade from 2001 till 2003.
Ajax's interest in re-signing Mido was first revealed in July but they could not reach a financial agreement with Boro over the transfer.
Mido, who was deemed a surplus at the Riverside, was eventually released by mutual consent to make his return to Ajax shortly afterwards.
During his previous spell with Ajax, Mido scored 23 goals in 57 matches. He was a prominent figure at the capital outfit at the time.
The former Egypt ace will be competing with Luis Suarez, the Eredivisie top scorer last season, and Dutch-Moroccan hitman Mounir El-Hamdaoui for a regular spot at Amsterdam Arena this season.
Mido has been suffering from recurring injuries and fitness problems for several years.
During his stay at Middlesbrough, the club he joined in 2007, Mido had three loan spells with fellow English sides Wigan Athletic and West Ham as well as Cairo giants Zamalek.
The nomadic player, who came through the youth ranks of Zamalek, played for four more European teams throughout his career in Gent, Celta Vigo, Marseille and AS Roma.