The increasing occurrence of prostate cancer in the United States has led to recommendations for routine prostate cancer screening in men aged 50 years and older. Although present methods of prostate cancer screening have not been shown to reduce mortality, screening using digital rectal examination or prostate-specific antigen does detect tumors at earlier stages. To assess whether trends in incidence and mortality rates are consistent with an increase in effective screening in New Mexico, we examined prostate cancer incidence rates calculated from data collected by the New Mexico Tumor Registry for the years 1969-1991, and mortality rates calculated from data collected by the New Mexico Bureau of Vital Statistics for the years 1958-1991. Population-based measures of prostate cancer screening frequency in New Mexico are not available for the period of this study; however, the proportion of prostate cancers detected by screening, as documented by a review of records from a random sample of prostate cancer cases, increased 3-fold, from 13% during the 1969-1972 period to 41% in the 1988-1991 period. During the period of study, age-adjusted incidence rates increased from 66.3 to 122.3/100,000 men. Stage migration from distant to earlier stages was apparent in the increase in the proportion of early stage cancers from 77.5 to 85.5%, and the decrease of distant stage cancers from 21.2 to 9.8%. Stage-specific incidence rates increased for local (87.3%) and regional stage cancers (283.0%), and decreased for distant stage cancers (16.0%).(ABSTRACT TRUNCATED AT 250 WORDS)