Totally 72 teams participated, 18 from Alpha Ethniki, 18 from Beta, and 36 from Gamma. It was held in 6 rounds, included final.
After the Group stage, there were interesting confrontations and many "protagonists" were eliminated by the competition continue. In the Second round, Olympiacos were eliminated by PAOK , Aris by Athinaikos and Iraklis by Xanthi, while in the Third round AEK Athens were eliminated by OFI. In the same round, Edessaikos, a Beta Ethniki team, reversed their loss 4–0 by Ionikos, achieving a draw with the same score in the second leg, in order however to be eliminated in penalty shootout.
The Final[1] was contested by Panathinaikos, for sixth time in the last 10 years, after the qualify against PAOK in semi-finals, and neophyte in Alpha Ethniki Athinaikos, for first and unique until now time in their history. That year, HFF decided the establishment of a two-legged final match, according to the model of Coppa Italia. Athinaikos selected as home of first match Apostolos Nikolaidis Stadium, instead of their neutral home, Municipal Stadium of Vyronas, while the second match became in the Athens Olympic Stadium. Panathinaikos won both matches and at the same time The Double.
Athinaikos, as finalist of competition, participated in the next season's European Cup Winners' Cup, for first and unique time in their history. Nikos Sarganis, Athinaikos goalkeeper, that had played in the first match of Final, failed to win the Cup with a fourth team, after Kastoria, Olympiacos and Panathinaikos. Also, the second match was the last for referee Meletis Voutsaras. For fourth possessed year, Dimitris Saravakos, with 10 goals, was elected as competition's first scorer.
Calendar[]
Round
Date(s)
Fixtures
Clubs
New entries
Group stage
26, 29 August & 2 September 1990
56
72 → 32
72
Round of 32
5, 12 December 1990 & 9 January 1991
32
32 → 16
none
Round of 16
30 January, 20 February 1991
16
16 → 8
none
Quarter-finals
13, 21 March 1991
8
8 → 4
none
Semi-finals
4, 24 April 1991
4
4 → 2
none
Final
15, 22 May 1991
2
2 → 1
none
Group stage[]
The phase was played in a single round-robin format. Each win would gain 2 points, each draw 1 and each loss would not gain any point.
The 47th Greek Cup Final was double-played this season. First leg was played at the Leoforos Alexandras Stadium, and second leg at the Olympic Stadium".