LUXEMBOURG (Bloomberg) - Google Inc., owner of the world's most-used Internet search engine, lost its bid to get European Union (EU)-wide trademark protection for "Gmail," the name of its web-based e-mail service.

The Gmail name is too similar to an existing German trademark, according to a ruling by the EU's trademark agency published on its Web site this week.

Google has been blocked from getting the EU rights to the name because of the trademark owned by German businessman Daniel Giersch for a slogan that includes the name "G-mail".

"There is a likelihood of confusion" between the two trademarks, the Alicante, Spain-based trademark agency ruled in the February 26 decision.

The common element Gmail is so similar that people "will be misled into thinking that the marks indicate a shared commercial origin."

Mr. Giersch, who received his German trademark in 2000, has been entangled in a series of European court cases against Google since the Mountain View, California-based company started its e-mail service in 2004.

Mr. Giersch, CEOof P1 Private GmbH, uses the name for a mail business that lets users send electronic files and messages through a central e- mail system. The G stands for his last name, he says.

Google can appeal the decision to the European Court of First Instance in Luxembourg, the EU's second-highest court. Google spokesman Kay Oberbeck had no comment when reached by telephone yesterday.

"I would expect them to appeal until they have no more legal recourse," Greg Sterling, an analyst at Sterling Market Intelligence in San Francisco, said by telephone today. "Ultimately, if they fail they will have no other way but to create a separate brand."

Mr. Giersch's full slogan - "G-mail...und die Post geht richtig ab," which translates as "G-mail ... and the mail really takes off" - helps promote the 33-year-old German's electronic mail-delivery business.

The trademark agency rejected Google's argument that there was no risk of confusion with its Gmail name when looking at Giersch's slogan as a whole.

The main element of his trademark is the word G-mail, according to the agency, the Office for Harmonisation in the Internal Market.

The second part of the slogan and the black and yellow colors, which are different from Google's, are of secondary importance, it said.

"The common element Gmail, with or without a hyphen, gives the signs an overall visual, phonetic and conceptual similarity, which is such that the relevant public" when confronted with the names in the electronic mail industry "will be misled," the agency ruled.

The ruling upholds a decision by the agency's lower board in January 2007 to reject Google's bid based on the "strong likelihood of confusion" with Mr. Giersch's German trademark.

"I find it striking that a US company clearly keeps losing in Germany and Europe-wide and yet it won't acknowledge that it is wrong," Mr. Giersch said in a telephone interview yesterday.

Google, which uses the name GoogleMail instead of Gmail in Germany, in July lost a German court bid to claim the right to Gmail from Giersch. Google also has used GoogleMail in the UK since 2005 when it settled a similar dispute with London-based Independent International Investment Research.

The EU agency, which grants trademarks that are valid across the 27-nation bloc, has the power to reject applications based on similar trademarks that already are registered in any EU country.