Objective: This study evaluated the Association of Community Organizations for Reform Now's (ACORN) efforts to increase the uptake of families claiming the earned income tax credit through door-to-door canvassing and managing free tax preparation clinics in three pilot cities. Method: The mixed-method program evaluation included administrative record review, a telephone survey (N = 1,063), and individual and focus group interviews. Results: During the 2003 tax year, ACORN prepared taxes at no charge for 3,850 families who collected a total of $4 million in earned income tax credit and other tax credits. In two pilot cities, ACORN led all other free sites in number of returns filed. Canvassing and word of mouth were the most productive marketing tools for the free tax preparation sites. Conclusions: Canvassing appears to be effective outreach in getting families to take advantage of free tax preparation. ACORN's approach to combining services and direct action organizing appears to be a good fit and sustainable. (Contains 8 tables.)