The group stage of the 1998–99 UEFA Champions League began on 16 September 1998 and ended on 9 December 1998.
Seeding was based on the UEFA associations 1998 ranking,[1] similarly to the previous season.
[2] Title holders and champions of nations ranked 1–5 were put in the Pot 1.
The remaining qualified runners-up (from the nations 6–8) and champions of top three nations ranked below 7 formed Pot 3.
Finally, the remaining six national champions formed Pot 4.