For the United States and selected states, this study generates indicators of the net census coverage error of Hispanics age 0 to 9 years in the 1990 census of population. Using annual Hispanic births (1980-1990), estimates of net Hispanic immigration, and estimated mortality, the "demographic accounting equation" is used to calculate the residual (difference) between the survived intercensal Hispanic population cohort age 0 to 9 years and the enumerated 1990 census Hispanic population that age.  This residual is an indicator of the net coverage error for young Hispanics.  Apart from the finding on Hispanic census undercount, the analytic study provides two additional observations, namely: (1) that the annual number of Hispanic births based only on origin of mother is inconsistent with the census- enumerated Hispanic origin universe (which includes children with Hispanic-only fathers as well as Hispanic mothers) and (2) that in the 1990 census-editing of item nonresponse, the characteristic "Hispanic origin" may have been over-allocated in the census 100-percent questionnaires relative to the allocation level used for the sample questionnaires.