A total of 72 teams from 48 of the 52 UEFA member associations participated in the 2004–05 UEFA Champions League (the exception being Liechtenstein, which does not organise a domestic league, Kazakhstan, Andorra and San Marino). The association ranking based on the UEFA country coefficients was used to determine the number of participating teams for each association:
Associations 1–3 each have four teams qualify.
Associations 4–6 each have three teams qualify.
Associations 7–15 each have two teams qualify.
Associations 16–52 (except Liechtenstein, Kazakhstan, Andorra and San Marino) each have one team qualify.
For the 2004–05 UEFA Champions League, the associations are allocated places according to their 2003 UEFA country coefficients, which takes into account their performance in European competitions from 1998–1999 to 2002–03.
Apart from the allocation based on the country coefficients, associations may have additional teams participating in the Champions League, as noted below:
(UCL) – Additional berth for the 2003–04 UEFA Champions League winners
Location of teams of the 2004–05 UEFA Champions League group stage. Brown: Group A; Red: Group B; Orange: Group C; Yellow: Group D; Green: Group E; Blue: Group F; Purple: Group G; Pink: Group H.
16 winners from the third qualifying round, 10 champions from countries ranked 1–10, and six second-placed teams from countries ranked 1–6 were drawn into eight groups of four teams each. The top two teams in each group will advance to the Champions League play-offs, while the third-placed teams will advance to the third round of the UEFA Cup.
Tiebreakers, if necessary, are applied in the following order:
Points earned in head-to-head matches between the tied teams.
Total goals scored in head-to-head matches between the tied teams.
Away goals scored in head-to-head matches between the tied teams.
^With Dynamo Kyiv leading 1–0, the match was abandoned at half-time after referee Anders Frisk was hit by an object thrown from the crowd. UEFA awarded Dynamo Kyiv a 3–0 win and ordered Roma to play their next two European games behind closed doors.
^Match was abandoned after 72 minutes as Milan lead 0–1 due to flares thrown onto the pitch by Internazionale fans, one of which struck Milan goalkeeper Dida.UEFA awarded Milan a 3–0 win (5–0 aggregate) and ordered Internazionale to play their next four European games behind closed doors.