The 1990 UEFA European Under-21 Championship, which spanned two years (1988–90), had 30 entrants. San Marino competed for the first time. USSR U-21s won the competition.
The 30 national teams were divided into eight groups (six groups of 4 + two groups of 3). The group winners played off against each other on a two-legged home-and-away basis until the winner was decided. There was no finals tournament or 3rd-place playoff.
The allocation of teams into qualifying groups was based on that of 1990 FIFA World Cup qualification with several changes, reflecting the absence of some nations:
Groups 1 and 2 featured the same nations
Group 3 did not include Iceland (moved to Group 4)
Group 4 did not include Wales, but included Iceland (moved from Group 3)