About three in four Americans favor drug testing for professional athletes, and a majority thinks such tests should be mandatory, according to a new Washington Post-ABC News public opinion poll.

In addition, 68 percent say professional athletes found to be using drugs for the first time should be banned or suspended from playing.

Support for drug testing apparently is fueled by the widespread belief that drug use is a major problem in professional sports. Testing was favored by large majorities in every region of the country and across all major demographic groups, especially among older people.

Overall, 73 percent of all people interviewed favored drug tests for professional athletes, including 52 percent who said testing should be mandatory. The figures were almost identical for people who said they were fans of professional sports.

Professional football players now take mandatory drug tests in a preseason physical and "upon reasonable cause" during the season. Many team owners have said they favor more frequent, mandatory tests.

Major league baseball players currently face no mandatory drug tests, but Commissioner Peter Ueberroth is pushing for mandatory testing of every player three times a year. This week, Donald Fehr, executive director of the Major League Baseball Players Association, criticized mandatory testing as being unnecessary.

Under Ueberroth's plan, players testing positive for drugs would be offered medical treatment and counseling but would not face punitive action such as suspension.

In all, 54 percent of the 1,506 people interviewed in the Post-ABC News survey came out for both mandatory testing and suspension of athletes found to be using drugs. Twelve percent said that first-time drug offenders on professional teams should be banned from all further participation in sports.

People believe college sports have less severe problems with drug use than professional sports, according to the poll. Thirty-seven percent said drug use is a major problem in college sports and 49 percent said it is a minor problem; only seven percent said drug use is not a problem.

By comparison, 59 percent said drug use is a major problem in professional sports, 34 percent said it is a minor problem, and three percent said it is not a problem.

Although most people think drug use is a serious problem in professional sports, more than six in 10 members of the public believe professional athletes use drugs no more than other people in similiar circumstances in other walks of life. Three in 10 said professional athletes are more prone to drug use.

The poll also found that one in three people believe that some players in professional sports "deliberately try to help the other team for gambling purposes" instead of giving "an honest effort." Thirty-seven percent of men said gambling affects some professional athletes, compared with 28 percent of women.

Ten percent described gambling problems as a major problem for professional sports.

The survey was conducted by telephone Oct. 24 to Oct. 28.