ATG Signs Reseller Agreement in Spain with Informatica El Corte Ingles.

CAMBRIDGE, Mass. -- ATG (Art Technology Group, Inc., NASDAQ: ARTG), whose licensed and on demand technology powers e-commerce sites and Corresponding e-marketing and customer service for the world's most customer-centric enterprises, today announced a Value Added Reseller agreement with Informatica El Corte Ingles, the systems integration and technology services division of the largest retailer in Spain. The systems integration company will also be providing delivery and implementation services supporting the ATG business applications in the Spanish market.

"Not only does Informatica El Corte Ingles provide services to its highly recognised parent company, but also to many of Spain's leading businesses. Their expertise in both the retail sector and in delivering web-enabled business critical software, some of which is complementary to our own, makes them an excellent partner for ATG in Spain," said Peter Ford, Alliances Director for Europe, Middle East and Africa for ATG. "We have already identified a number of opportunities we are working on together where the combined value of our skills and experience can deliver tangible business benefits to the clients."

"We see this relationship with ATG as a strategic next step for our business. Having already established our reputation in our market as a provider of quality solutions for the web-based economy, the next generation of customer interaction on the web is something we see as key to the continued development of e-Commerce. ATG's customer experience management solutions are recognised as defining the standard in this field and we felt they would complement the solutions we deliver to our clients," said Juan Jose Pradales, Director of the Informatica El Corte Ingles e-Business Division.

About Informatica El Corte Ingles

Informatica El Corte Ingles is the information technology company of Grupo El Corte Ingles, the largest retailer in Spain with an annual income across its operations of over EUR 15Bn. Informatica El Corte Ingles provides solutions and computer services for large companies as well as for public administrations. With a revenue of 980,70 million euros in 2005, the IT company is the largest of its kind in Spain, based upon Spanish capital, and employs a workforce of more than 2,000 IT professionals.

Within its eBusiness Division, it has a Innovation Area in which nearly 300 professionals work to create new Internet solutions for businesses and the electronic Public Administration. For more information about Informatica El Corte Ingles, please visit www.ieci.es.

About ATG

ATG (Art Technology Group, Inc., NASDAQ: ARTG) makes the software that the world's most customer-conscious companies use to create a more relevant and consistent customer experience, throughout the marketing, commerce, and service lifecycle, and across the Web, e-mail, call center, and mobile channels. Offering an alternative to the traditional silo-based approach to customer-facing applications, ATG Wisdom(TM) is the company's strategy for delivering a seamless, more compelling, and mutually valuable experience to each customer and segment. The company fulfills this strategy by providing fully integrated best-of-breed product suites installed on-premise or delivered on-demand. ATG's solutions power over 600 major brands, including A&E Networks, Airbus, American Airlines, American Eagle Outfitters, Best Buy, Boeing, Cingular Wireless, DirecTV, France Telecom, Friends Provident, Hewlett-Packard, Hotels.com, Hyatt Hotels, HSBC, InterContinental Hotels Group, Kingfisher, Louis Vuitton, Merrill Lynch, Neiman Marcus, Philips, Procter & Gamble, Symantec, T-Mobile, Target, US Army, US Navy, Warner Music, and Wells Fargo. The company is headquartered in Cambridge, Massachusetts, with additional locations throughout North America and Europe. For more information about ATG, please visit www.atg.com.

(C) 2006 Art Technology Group, Inc. ATG and Art Technology Group are registered trademarks, and ATG Wisdom is a trademark of Art Technology Group, Inc. All other product names, service marks, and trademarks mentioned herein are trademarks of their respective owners.

This press release contains forward-looking statements for purposes of the safe harbor provisions under The Private Securities Litigation Reform Act of 1995. These statements involve known and unknown risks and uncertainties that may cause ATG's actual results, levels of activity, performance or achievements to be materially different from any future results, levels of activity, performance or achievements expressed or implied by such forward-looking statements. Important risk factors affecting ATG's business generally may be found in its periodic reports and registration statements filed with the Securities and Exchange Commission at www.sec.gov . Risk factors related to the subject matter of this press release include the possibility that the ATG product deployment will not be successful, on time or significantly enhance the user's Internet experience or will not increase customer revenue across brands; that those customers leveraging ATG will not have the opportunity to increase revenue and decrease future costs; the need to adapt to rapid changes so products do not become obsolete; the possibility of errors in ATG's software products; the possibility that the solution will not make customer implementations faster or more flexible or permit the customer to meet its customer-facing or infrastructure requirements; that the ATG product will not continue to be integrated with third party applications servers or will not support all Web services enabled systems; that ATG's product strategy may change in the future; and the risks and costs of intellectual property litigation. ATG undertakes no obligation to update any of the forward-looking statements after the date of this press release.