Infant mortality varies considerably among racial/ethnic groups in the United States. For groups other than whites and blacks, previously published rates based on the vital statistics system have been underestimated because of inconsistencies in the classification of race and Hispanic status on birth and death certificates. For this report, infant mortality rates (IMRs) are based on the 1983 and 1984 linked birth and infant-death files, and mother's race and Hispanic origin are reported in accordance with information shown on the birth certificates. Overall, Asians have somewhat lower infant mortality rates than whites, but the rates vary from 6.0/1,000 among Japanese mothers to 9.0/1,000 among "other Asian" mothers. Hispanic mothers show even wider variation: from 7.8/1,000 among Cubans to 12.9/1,000 among Puerto Ricans. Blacks have an IMR twice as high as that for whites, and the rate for American Indians is nearly 60% above the rate for whites. Mexicans are the third largest minority group in the United States, accounting for one-quarter million births per year. Despite a high rate of poverty and low use of prenatal care, Mexicans have approximately the same IMR (9.0/1,000) as non-Hispanic whites. Further study of this group could assist in the development of prevention strategies.