After months of legal wrangling, a federal appeals court Tuesday ruled that the national do-not-call registry is constitutional, allowing the Federal Trade Commission and the Federal Communications Commission to continue to operate and enforce the list.

“The court has made it clear that the FTC and FCC can and will continue to protect consumers’ privacy at home,” FTC chairman Timothy J. Muris said in a statement.

He called the ruling a “major victory” for American consumers.

Last fall, the legality of the list came into question when a district judge ruled that it was unconstitutional on free-speech grounds because it applied to calls from businesses but not charities.

The popular registry includes more than 55 million phone numbers registered by consumers tired of being interrupted by telemarketing calls.

The Direct Marketing Association, one of a number of groups that last fall challenged the constitutionality of the list, said it is reviewing the court’s decision with its legal counsel. The DMA also said that the online registration process has not been safeguarded to prevent abuse, such as stopping businesses from registering the phone numbers of customers’ names so competitors cannot call them.

Last month, President Bush signed a bill requiring telemarketers to scrub their files against the national registry once a month. The requirement had been quarterly.

The FTC said that in 2003 fewer than 45 companies have received more than 100 complaints from consumers. Some 150,000 possible violations have been reported and top violators are being looked at, the FTC said.

After months of legal wrangling, a federal appeals court Tuesday ruled that the national do-not-call registry is constitutional, allowing the Federal Trade Commission and the Federal Communications Commission to continue to operate and enforce the list.

“The court has made it clear that the FTC and FCC can and will continue to protect consumers’ privacy at home,” FTC chairman Timothy J. Muris said in a statement.

He called the ruling a “major victory” for American consumers.

Last fall, the legality of the list came into question when a district judge ruled that it was unconstitutional on free-speech grounds because it applied to calls from businesses but not charities.

The popular registry includes more than 55 million phone numbers registered by consumers tired of being interrupted by telemarketing calls.

The Direct Marketing Association, one of a number of groups that last fall challenged the constitutionality of the list, said it is reviewing the court’s decision with its legal counsel. The DMA also said that the online registration process has not been safeguarded to prevent abuse, such as stopping businesses from registering the phone numbers of customers’ names so competitors cannot call them.

Last month, President Bush signed a bill requiring telemarketers to scrub their files against the national registry once a month. The requirement had been quarterly.

The FTC said that in 2003 fewer than 45 companies have received more than 100 complaints from consumers. Some 150,000 possible violations have been reported and top violators are being looked at, the FTC said.