The company is the first national partner for the event, which will be staged at the National Indoor Arena in Birmingham, UK from March 2-4, 2007.
INTERSPORT, which has 4,800 stores worldwide, will be providing all the uniforms for up to 800 volunteers.
Communications manager for the retailer, John Oldfield, said: "As a local company we feel it is important to support sports events being staged in our home city but this event also has an international significance and with stores in 29 countries INTERSPORT is a recognised international brand."
The 29th European Athletics Indoor Championships, the biggest indoor athletics even in Europe, will see more than 600 athletes from around 49 countries compete. It is expected to attract around 15,000 spectators.
