An estimated $1.5 billion in EITC benefits was left unclaimed last year, and the Internal Revenue Service reports that 20 percent of taxpayers who qualify don't claim the credit, which can be worth more than $4,700 per family.

Block said that it helped 4.5 million taxpayers claim $10 billion in EITC benefits in 2007, accounting for nearly a quarter of all claims. 

"The EITC is among the most complicated provisions in the tax code, and audit rates for this credit are among the highest for any group, so getting help from a qualified tax preparer is important to ensure an accurate tax return," said Tim Gokey, group president of H&R Block Retail Tax Services. "Other key benefits - like food stamps or children's health insurance - can add more than $9,000 to a family's income. They are widely overlooked, so we're committed to raising awareness about these important benefits."

Block will partner with community-based organizations, such as the United Way and Operation HOPE, to promote EITC through outreach and education campaigns in 60 cities. The tax preparer will also provide tax preparation software to 100 Volunteer Income Tax Assistance (VITA) sites nationwide in 2008.

Other intiatives include alerting Block clients to their possible eligibility for means-tested government benefits and provide contact information for government agencies, enabling most EITC-eligible taxpayers to prepare tax returns free through H&R Block's Free File Alliance program, and partnering with ACORN and Beehive.org to provide free tax preparation software and financial education to low- and moderate-income Americans.