Aiming to be the first club to retain world football's most coveted club trophy for 25 years, the road for ten-time winner Madrid leads to five-time champion Liverpool on Oct. 22.
"It's going to be a very tough game in their home," said Cristiano Ronaldo, whose Madrid team also faces Basel and newcomer Ludogorets Razgrad of Bulgaria. "I think in general the group is nice. It's going to be good for Real Madrid."
Madrid and Liverpool's past history includes the English team's victories in the 1981 final and a 4-0 rout at Anfield in the Round of 16 six seasons ago.
Star forwards Luis Suarez and Zlatan Ibrahimovic can both return to former club Ajax in a group where their current teams, Barcelona and Paris Saint-Germain, respectively, are favoured. APOEL of Cyprus completes the group.
Suarez is next eligible for the Champions League, after serving his four-month ban for biting, on Nov. 5 when Barcelona visits Amsterdam. There, he earned the nickname "Cannibal of Ajax" for sinking his teeth into a Dutch league opponent in 2010.
In a draw heavy with England vs. Germany repeat rivalries, Bayern Munich will face Manchester City and Arsenal has been grouped with Borussia Dortmund, each for the third time in four seasons.
Bayern and Man City also played CSKA Moscow last season, and they are now joined by Roma in perhaps the most difficult quartet.
"I think this is the toughest group," Man City director of football Txiki Begiristain said. "We are ready to fight for everything."
The eight four-team groups begin play on Sept. 16-17. The top two teams in each group advance to knockout round.
Madrid and Liverpool provide almost half of the 36 European Cup and Champions League titles shared among 10 former winners in the draw.
Liverpool, runner-up to title-winning Man City last season, returns to the Champions League after a four-season absence.
"That was last season's hard work, what we were working toward," manager Brendan Rodgers said, "getting Liverpool back into a competition where we are synonymous."
Liverpool kicks off on Sept. 16 hosting Ludogorets which debuted in European competitions just two years ago.
The Bulgarian team had perhaps the most memorable qualifying route: It got a 90th-minute equalizer in a playoff Wednesday against Steaua Bucharest before defender Cosmin Moti had to go in goal in extra time and saved two penalties in the decisive shootout.
Arsenal and Dortmund, both beaten finalists in recent years, will also face Galatasaray and Anderlecht.
"We surely know Arsenal the best," said Dortmund coach Juergen Klopp, whose team advanced with the top-seeded English side a year ago.
Chelsea and Schalke also advanced together last season and now will play Sporting Lisbon and Maribor.
Atletico Madrid, last season's runner-up, was grouped with Juventus, Olympiakos and Malmo, the 1979 runner-up as a semi-professional club.
"It's a likable group. Of course there are hidden dangers," said Juventus chief executive Giuseppe Marotta, noting a home opener against Malmo, a clear league leader deep into the Swedish season.
In perhaps the toughest group to predict, Benfica is with Zenit St. Petersburg, Bayer Leverkusen and Monaco. Despite having Colombia forward Radamel Falcao, Monaco's absence from UEFA competitions since 2006 left it among the lowest-ranked teams.
The longest travel times face the group of Porto, Shakhtar Donetsk, Athletic Bilbao and BATE Borisov of Belarus.
By UEFA order for security reasons, Shakhtar will play home matches in Lviv in western Ukraine. Its home stadium in eastern Ukraine which borders Russia, was damaged this week in the conflict there.
The Champions League's commercial strength allows UEFA to share nearly 1 billion euros ($1.34 billion) in prize money among the 32 teams.
UEFA pays a basic 8.6 million euros ($11.5 million) fee for entering the group, plus 1 million euros ($1.34 million) per win and 500,000 euros ($670,000) per draw. Teams also get a share of television rights money.
The final will be played at the Olympic Stadium in Berlin on June 6.