This report is one in a series of reports that compares data from the American Community Survey (ACS) with data from the Current Population Survey (CPS) Annual Social and Economic Supplement (ASEC). The data analysis in this report focuses on comparisons of national estimates of in come between the 2004 and 2005 ACS and the 2005 and 2006 CPS ASEC (income years 2004 and 2005). This analysis also compares state level estimates from the 2005 ACS with 2-year average estimates from CPS ASEC. The report looks for both statistical and substantive differences, and possible explanations. This report also examines methodological differences in the collection of income data between the two surveys.