Abstract OBJECTIVE: Multiple reports indicate that esophageal adenocarcinoma incidence has increased during the past 20 yr, especially in non-Hispanic white men. We retrospectively reviewed adenocarcinoma and squamous cell carcinoma cases in our heterogeneous state population to determine the effect of ethnicity on histology. METHODS: We searched the New Mexico Tumor Registry for all cases of esophageal cancer from 1973 to 1997. Inclusion criteria included histological diagnosis of adenocarcinoma or squamous cell carcinoma, self- reported ethnicity, and gender. Age-adjusted incidence rates for both adenocarcinoma or squamous cell carcinoma were compared among ethnic groups in 5-yr intervals. RESULTS: Six hundred fifteen patients met inclusion criteria. Esophageal adenocarcinoma age-adjusted incidence rates/100,000 increased significantly during the 25-yr period: 1973–1977, 0.25 cases; 1978–1982, 0.33 cases; 1983–1987, 0.45 cases; 1988–1992, 0.85 cases; and 1993–1997, 1.19 cases; p < 0.001. In comparison, squamous cell carcinoma age-adjusted incidence rates did not increase significantly during the study period. In non-Hispanic whites, the histological age-adjusted incidence rate changed during the 1993–1997 period compared to other periods: 1993–1997, squamous cell carcinoma 1.01 and adenocarcinoma 1.42, p < 0.001. In Hispanics, the age-adjusted incidence rate of adenocarcinoma increased significantly in the fifth period compared to other periods, p < 0.001. In all minority groups, squamous cell carcinoma remained the predominant type. CONCLUSIONS: Esophageal adenocarcinoma age-adjusted incidence increased in New Mexico from 1973 to 1997. This increase was found in non-Hispanic whites and Hispanics and became predominant in non-Hispanic whites. Squamous cell carcinoma remains the primary type in minorities. This study suggests that ethnicity may influence esophageal cancer histology or ethnic background may place an individual at increased risk for certain types of esophageal cancer.