Comcast’s claim that its Xfinity Internet is the “fastest in the nation” is demonstrably false and has led to a request by the National Advertising Division, a self-regulating industry group, that Comcast pull the ads.

The NAD found Comcast was basing its claim on this 2011 PC Magazine article that gave high ranks to Comcast, along with Cox and Charter, for fast download speeds. But PC Magazine‘s study failed to account for Verizon FiOS and other fiber broadband providers, who routinely deliver upload and download speeds far in excess of what Comcast can offer.

The report (Case #5463 — available only to subscribers), recommends that Comcast stop making the claims in markets where fiber networks like FiOS are available. Where the company does choose to run the ads, they should disclose the PC Magazine report as its source.

Comcast’s cable broadband can deliver faster speeds than traditional telephone company DSL, but fiber broadband can deliver much faster service with equal upstream and downstream speeds of up to 1Gbps.

Comcast said it would consider the NAD’s recommendations.