ZURICH, Switzerland — Evander Holyfield is returning to the ring at age 46, setting his sights on becoming undisputed heavyweight champion again.

Holyfield will fight 7-foot WBA champion Nikolai Valuev next month. A victory will make him the oldest man to claim a world heavyweight title and the first to win it five times.

"My goal is to be undisputed champion not just to win one title," Holyfield said at a news conference Tuesday at the Hallenstadion, where the fight will take place on Dec. 20.

"I think people make too much about age," he said. "I haven't fought in a year but I will be ready."

Holyfield underwent five hours of medical tests in Germany on Monday to show he was ready for the physical challenge of facing the Russian champion, who is likely to take a 100-pound advantage into the ring.

Holyfield, who had his license to box in New York state revoked three years ago, said he could do no more to reassure people worried about his health.

"They will have to see the fight and know for themselves," he said. "I have taken care of myself and if I couldn't fight then I wouldn't fight."

Holyfield said he never expected to be "the old guy" in the ring, recalling that his first defense after becoming undisputed champion in 1990 was a points victory against 42-year-old George Foreman.

"I didn't want to fight him," Holyfield said. "My manager said he (Foreman) earned his shot so do it. I did and it was a tough fight."

Foreman went on to become the oldest man to win a heavyweight title at 45, knocking out Holyfield's conqueror Michael Moorer.

Holyfield has reunited with trainer Tommy Brooks and his first professional manager, Ken Sanders, to try to regain the WBA title he last lost in 2001 to John Ruiz.

Sanders said the fighter's publicized financial problems were solved and he was coming back for a title shot rather than the money.

"If it was not a championship fight we would not have taken it," Sanders said.

Holyfield is expected to earn between $750,000 and $1 million for fighting Valuev, with bigger purses waiting for unification fights.

"It is not much for him to fight for the championship," Sanders said. "You can make $10 million for the next fight."

Holyfield has the potential in the next five years to match his career earnings of $200 million, the manager said.

Sanders added: "And he's going to keep it this time, I'm going to see to that."

The Klitschko brothers currently hold four other versions of the heavyweight title. The 37-year-old Vitali has the WBC belt, while 32-year-old Wladimir holds the IBF, WBO and IBO versions.

The 35-year-old Valuev described Holyfield as a legend and said he watched his fights 10 years ago, and dreamed of one day meeting him in the ring.

Although the fight is being held in Switzerland, it is being promoted by Germans and Holyfield's fighting license has been issued by the boxing authority of neighboring Austria.

Promoter Kalle Sauerland said the medical tests appeared to show that Holyfield, who will train in Houston, Texas, was "more than fighting fit."

"We have gone to the best doctors and we have gone for the most thorough checks," Sauerland said. "We are all in the clear."

Holyfield won four fights in Texas before his most recent bout, in October last year, when he lost a unanimous decision to then-WBO champion Sultan Ibragimov in Moscow.

He said he had overcame doubts about him when beating Mike Tyson for the first time in 1996.

"They said I was going to get killed," Holyfield said. "I had to remind them that I didn't get there because somebody chose me, but I got there because I worked and I was able to beat him.

"The only way you can reach your goal is if you do the things you know you can do — and I do box real well," Holyfield added.