This paper proposes a measurement change for the Special Supplemental Nutrition Program for Women, Infants and Children (WIC) based on the Current Population Survey’s Annual Social and Economic Supplement (CPS ASEC). Working papers on the Supplemental Poverty Measure (SPM) have estimated WIC participation based on the number of WIC family cases and not on the number of individual participants. Identifying only one WIC beneficiary per eligible family has likely resulted in an undercount of WIC benefits. To address the problem, we propose assigning WIC participation in the CPS ASEC at the household level and then designating as beneficiaries all eligible women and children in households reporting WIC participation. Using this method, the SPM rate for 2011 decreased by less than one tenth of a percentage point or by 125,000 fewer people in poverty. Although the resulting WIC participation estimates were lower than those from administrative records, the proposed method is an improvement. Based on the results in this paper, a change in the way we estimate WIC in the CPS ASEC is recommended.