Beginning in the late 1980s, a large increase in incidence rates for prostate cancer occurred in association with increased prostate-specific antigen (PSA) screening. In New Mexico, the increased screening was associated with earlier detection of cancers and decreased prostate cancer mortality, suggesting that PSA screening may be effective. PSA screening has become a controversial topic of public debate, and anecdotal reports from physicians indicated that prostate cancer screening practice patterns were changing in New Mexico. To assess whether PSA-associated trends in prostate cancer incidence were continuing, we examined incidence rates from 1989 to 1993 among men in New Mexico. From 1989 to 1992, age-adjusted rates increased substantially for non-Hispanic whites (77%), Hispanics (50%), and American Indians (27%). Although rates increased for all stages combined, incidence rates decreased for distant-stage disease, especially for non-Hispanic whites, indicating a continuing trend toward earlier detection. In 1993, incidence rates unexpectedly decreased from 203 to 158/100,000 in non-Hispanic whites, largely as a result of changes in rates in men over age 65 years. Although incidence rates decreased, the trend toward earlier detection was maintained for non-Hispanic whites. In contrast, among Hispanic and American Indians, rates did not change substantially between 1992 and 1993. Because the epidemic in prostate cancer was associated with increased PSA screening, it is likely that the trends for non-Hispanic whites are also related to PSA screening. We suggest that the decrease in rates and the continued stage shift are consistent with repeated screening of men in the population at risk.