This paper shows trends in underreporting of SSI, AFDC/TANF, Food Stamps, and Medicaid/SCHIP from 1993 to 2005 in the Current Population Survey (CPS) and discusses the extent of CPS allocation for nonresponse. Comparisons are made to the Survey of Income and Program Participation (SIPP) for 1997 and 2002. Baseline and poverty estimates from the 2004 simulation of the TRIM3 microsimulation model are presented to demonstrate the use of microsimulation in correcting for underreporting of means-tested benefits in the CPS.