Peter G. Angelos, the Orioles' majority owner, could not be reached for comment yesterday but has previously denied the allegation.
The investigation comes two months after an Orioles vice president made statements that suggested the team had a policy of refusing to bid on players who had defected from Cuba.
Helms, the North Carolina Republican who is chairman of the Senate Foreign Relations Committee and is a vocal critic of Cuban dictator Fidel Castro, has asked Justice officials to determine whether the Orioles blackballed Cuban defectors as a goodwill gesture to Havana. The Orioles and Cuban team played two exhibition games last year.
In a letter to Helms, the Justice Department confirmed that officials have "opened an independent investigation of the Baltimore Orioles to determine whether the alleged player hiring policies and practices violate" federal law.
Kara Peterman, a Justice Department spokeswoman, declined to discuss the case, which is a civil action that could result in fines.
A spokesman for Helms said the senator was pleased that the Justice Department has decided to take on the case.
Mark Thiessen, the spokesman, said Helms would also seek an inquiry by the federal Equal Employment Opportunity Commission, which investigates job discrimination.
At issue are comments made in May to the Washington Times by Orioles Vice President Syd Thrift about the team's apparent lack of interest in Cuban players.
"We - Mr. Angelos in particular - feel that it best not to do anything that could be interpreted as being disrespectful or ... encouraging players to defect," the newspaper quoted Thrift as saying then.
The Justice Department investigation was first reported by the Times yesterday.
A few days later, the congressman received a letter from Selig saying he was aware of the allegation and was "looking into it," said Dan Lara, a Goodling spokesman.
In addition, Judicial Watch, a conservative advocacy group, has said it has filed a complaint against the Orioles with the EEOC. Officials at the EEOC declined yesterday to say whether they were investigating the matter.
Thiessen, Helms' spokesman, suggested yesterday that the Orioles, who were 8 1/2 games behind the first-place New York Yankees in the American League East before last night's game, might benefit from having a few Cuban defectors. About two dozen Cuban ballplayers have defected to the United States.