Both have strengthened their squads with key transfers and the pair lead the betting by a big margin over the other clubs.
For the Bavarians, however, it does not look like it is going to be as easy as last season when they clinched the Bundesliga crown by March and in record time.
"This season we will need some time," coach Pep Guardiola said last week. "At the moment I have only eight or nine players who are fully fit."
A string of injuries, including key midfielder Javi Martinez's cruciate ligament tear last week, have forced Bayern to reconsider their transfer options.
Apart from Martinez, who was set to play the central role in a new-look three-man defence, Guardiola, in his second season in charge, will also have to do without fellow holding midfielder Bastian Schweinsteiger for several weeks or even months.
A nagging knee injury that Schweinsteiger carried through Germany's World Cup-winning campaign last month has come back to haunt him, ruling him out of the Bundesliga start.
"Now it seems his knee is signalling for a break. That is something that is hurting Bayern," Guardiola said.
Winger Franck Ribery, midfielder Thiago Alcantara and defender Rafinha are also out injured.
With Bayern's six World Cup winners still to hit top form after a long campaign for club and country and their recent return to training, last term's domestic double winners lost their season-opening German Super Cup to Dortmund 2-0.
Having eased through their German Cup first round tie against third-tier Preussen Muenster, Guardiola is well aware that time is not on his side.
With Vfl Wolfsburg awaiting on Friday in the season opener, the Spaniard is under pressure to start delivering just like he did in his first season in charge.
Newcomer Robert Lewandowski, last season's Bundesliga top scorer, has yet to hit the target in a competitive game for Bayern but the fans are hopeful the Poland striker will give them lots to cheer this season with goals and assists.
Dortmund lost Lewandowski to Bayern on a free transfer but coach Juergen Klopp hopes Italy forward Ciro Immobile and Adrian Ramos will be efficient replacements.
With winger Pierre-Emerick Aubameyang in fine form already, having scored in the Super Cup and the German Cup, Dortmund look set to take the fight to Bayern this season.
Winger Marco Reus, who is another Bayern target, and central defender Neven Subotic are back from injuries and playmaker Ilkay Guendogan, who missed the whole of last season with a back problem, also looks to be on track for his Dortmund comeback.
Fellow Champions League competitors Schalke 04 did not splash out in the transfer market but Cameroon international Eric Maxim Choupo-Moting and winger Sidney Sam will add more depth and creativity to their attack.
Nevertheless, mercurial Schalke are outsiders for their first Bundesliga title.
Bayer Leverkusen, who finished fourth last season, have brought in hugely talented attacking midfielder Hakan Calhanoglou and Swiss striker Josip Drmic, who will add to their firepower alongside the established Stefan Kiessling.
Whether Leverkusen, nicknamed 'Neverkusen' for their failure to win trophies, have enough about them to make a serious run for their maiden Bundesliga title remains to be seen.
"The players can go ahead and dream and then they can articulate those dreams," Leverkusen's new coach Roger Schmidt said, confirming his team were targeting the title.
"When they say that (they want to win the title) then everyone knows exactly what they need to do if they have such a target."
Wolfsburg and Borussia Moenchengladbach are eager to break into the top four with the former bringing in Denmark striker Nicklas Bendtner to help them score goals.
Attacking midfielder Aaron Hunt has also come in from Werder Bremen as the Volkswagen-owned club, champions in 2009, look to improve on last season's fifth place finish.
At the other end of the table, Bundesliga newcomers Paderborn, with the smallest budget in the division, will be battling for survival from the first game while returning FC Cologne will be looking to stay up longer this time.
Hamburg SV, who needed a relegation playoff to survive in the top flight and remain the only team to have played all 51 seasons in the Bundesliga, are hoping to avoid any such dangerous adventures this season.
Forward Pierre-Michel Lasogga made a permanent move to Hamburg after his loan spell from Hertha Berlin last season and the former European champions are counting on his goals to lift them higher up the table.