This study measures the validity of self-reported mammography and Pap smear usage in Mexican-American women. We compared Pap smear and mammography reports in medical records to self-reports obtained in a household survey of 450 women in El Paso, Texas. The women were generally low-income, older, and Spanish-speaking. Forty-six percent of self-reported Pap smears in the previous year were verified (60.8% within previous two years, 67.1% within previous three years). Forty-nine percent of self-reported mammograms within the previous year were verified (74.7% within previous two years). For both Pap smears and mammograms, twice as many tests in the past five years were reported as were documented. Self-reports of Pap smears at a public health clinic were more valid than those at other sites. Denials of mammography within the past five years were more accurate (97.5%) than denials of Pap smears (81.8%). We conclude that self-reports of mammograms and Pap smears in Mexican-American women greatly overestimate the prevalence of screening. Intensive cancer prevention activities in this population are needed to approach the Year 2000 Objectives set by the U.S. Department of Health and Human Services.