Pacquiao weighed in at the maximum 147 pounds, while Marquez weighed in at 143 pounds.
Marquez pumped his fists at the crowd and flexed his muscles, sporting a gold chain, before the two fighters stared each other down in front of the cameras.
After the weigh-in, Marquez told HBO's Larry Merchant that "it was gonna be a war," per his translator, noting that it was the most important fight between the two to show who the better man was.
Talking with Merchant before the weigh-in, Pacquiao's trainer, Freddie Roach, said that he was joking when he hinted before the fight that Marquez used performance-enhancing drugs.
On the other hand, he said he believes Marquez's noticeably beefed-up appearance will actually hurt the 39-year-old Mexican, claiming it will slow him down.
Roach also said that he offered a little incentive for Pacquiao to be more aggressive in their sparring sessions before the fight. He said he offered the 33-year-old Filipino $1,000 for each knockdown in the session and Pacquiao scored four knockdowns.
Marquez's trainer, Nacho Beristain, told Merchant that the added muscle would be better for the Mexican and said he would still have the speed.
Pacquiao has a 2-0-1 record against Marquez, but all three fights have been close. Some believed Marquez won their third fight in November 2011, but the judges saw it otherwise, handing Pacquiao a majority decision.
Since then, Pacquiao has lost a controversial decision to Timothy Bradley Jr., but he actually looked better and more aggressive in the June bout than he did in the third fight with Marquez.
Marquez beat Sergey Fedchenko via unanimous decision in April.
In the November 2011 weigh-in, Pacquiao was listed at 143 pounds, while Marquez was listed at 142 pounds.
One last thing: Pacquiao told Merchant that he still has the fire in his belly, something that was questioned after his third fight with Marquez.