This cross-sectional study assessed: (a) awareness and knowledge of federal dietary tools (MyPyramid, Food Guide Pyramid (FGP), and food labels (FL)), and (b) the influence of acculturation and state of residence on FGP knowledge (FGPK) indicators among low-income Latina WIC participants (N = 479) living in Connecticut, Ohio, Texas, and California. Participants were familiar with FGP but only 37% recognized MyPyramid. FGPK was highest for fruits (71%) and lowest for the 'breads and cereals' group (12%). Less than half (47%) used FL's when grocery shopping. Living in OH, was associated with the lowest FGPK. Multivariate analyses showed that more acculturated individuals living in CT/CA had better FGPK than participants living in TX and their less acculturated counterparts in CT/CA. The forthcoming revised federal dietary tools need to be adequately disseminated among Latinos, with special emphasis on those with lower acculturation levels, living in rapid emerging Latino communities or in the US-Mexico border.