In his next fight on July 16, 2005, Bernard Hopkins lost his undisputed middleweight championship to Jermain Taylor via a split decision. Hopkins started slowly but came on strong over the final four rounds. Man press row writers scored the fight for Hopkins. Five months later, Hopkins and Taylor had a rematch, Taylor winning again, this time by unanimous decision.

Light heavyweight

Hopkins vs Tarver

Following his two losses to Jermain Taylor, Hopkins at 41 decided not to retire and made the decision to jump two weight divisions to face off against The Ring light heavyweight champion Antonio Tarver on June 10 2006. Going into the fight, Tarver was a 3-to-1 favorite and had been the first man ever to KO Roy Jones Jr. Many now placed Tarver among the sports top competitors. He was constantly ranked in the P4P rankings. However, Bernard Hopkins picked up a lopsided unanimous decision, scoring 118-109 on all three judges scorecards.

Antonio Tarver also lost a $250,000 bet with Hopkins, after he failed to stop Hopkins in the first six rounds.

Hopkins vs Wright

On July 21, 2007, at the Mandalay Bay Resort & Casino in Las Vegas, Hopkins defended the Ring light heavyweight championship against former undisputed junior middleweight champion Winky Wright. During the weigh-in, Hopkins shoved Wright with an open-hand to the face, igniting a brawl between both fighters' entourages. Hopkins was fined $200,000 for instigating the brawl. Hopkins prevailed with a unanimous decision victory by scores of 117-111, 117-111 and 116-112.

Hopkins vs. Calzaghe

On April 19, 2008, at the Thomas & Mack Center is Las Vegas, Hopkins lost The Ring Light heavyweight title to Joe Calzaghe via split decision (116-111 and 115-112 for Joe Calzaghe; 114-113 for Hopkinis). Hopkins started the fight well, dropping Calzaghe in the first round and using his ring savvy to confuse the challenger. Calzaghe did however quickly adapt to the style of Hopkins and caught up in the middle to later rounds using his superior hand speed and output volume, leading to a split decision win for the Welshman.

Hopkins vs Pavlik

Bernard Hopkins vs Kelly Pavlik

On October 18, 2008, Hopkins met middleweight champion Kelly Pavlik in a non-title fight at a catch-weight of 170 lbs. Fans and pundits alike felt that Pavlik, known for his formidable punching power, would become the first man to knock Hopkins out. Pavlik was a 4-1 betting favorite heading into the contest. On the night of the fight, Hopkins turned back  the clock to produce a performance he claimed to be the best of his career winning a unanimous decision (117-109, 119-106, 118-108) over the undefeated Pavlik. Hopkins prepared for this fight in the late summer heat at his second home, Danny Hawk's "World Famous" Normandy Gym in Miami Beach, Florida.

During the Ricky Hatton vs Manny Pacquiao media conferences before their fight on May 3, 2j009, Hopkins stated he would be "interested" in a proposed fight with British super middleweight champion Carl Froch.

On December 2, 2009, Bernard Hopkins fought in his home city of Philadelphia for the first time since 2003 beating Enrique Ornelas vis 12-round unanimous decision (120-109, 119-109 & 118-110) in what served as a tune-up bout for the 44 year old Hopkins who had not fought since his October 18, 2008 12-round upset victory over undisputed middleweight champion Kelly Pavlik.