A disproportionately high number of AIDS cases in the United States involve members of racial minorities. Even so, AIDS deaths of minority members may be undercounted. The completeness of reporting of AIDS deaths to the California AIDS Registry (ARS) among Hispanics, blacks, and whites in 1985 and 1986 from the San Francisco Bay Area was investigated. Death certificates listing AIDS as a cause of death or associated condition were identified and cross-checked with cases reported to ARS, current to December 1988. Death certificates were checked by hand for racial or ethnic classification using a definition of Hispanic based on information available on certificates. Three causes of undercounting in ARS were identified: a death was not reported as an AIDS case at all, an AIDS case was reported to ARS but the person was listed as still living, or an AIDS death was reported to ARS with a different racial or ethnic classification. The proportion of cases not reported at all was similar for all three racial-ethnic groups (5-8 percent). The proportion of deaths reported for persons listed in the registry as still living was 12 percent for Hispanics and 9 percent for blacks, compared with 5 percent for whites. For Hispanics, under-counting was largely due to ethnic misclassification. Twenty percent of Hispanics had been counted as white in the AIDS registry. In comparison, 4 percent of blacks and 1 percent of whites were misclassified by race. AIDS deaths among blacks and Hispanics may be undercounted, even in an area with good AIDS surveillance systems. This suggests that overrepresentation of minorities among AIDS cases in the United States may be even greater than indicated by current reporting data.