The stage of cancers at the time of diagnosis for 10 major sites of disease from patients treated at two Medical College of Wisconsin teaching hospitals was analyzed from tumor registry data and compared from the years 1983, 1987, and 1991. A trend toward earlier stages of cancer of major sites was noted, with patients having in situ or localized disease increasing from 35% in 1983 to 48% in 1991. Patients with breast cancer demonstrated the strongest trend, with 44% of the cases representing in situ or localized disease in 1983 compared to 61% in 1991 (p = 0.03). A shift toward earlier stage of cancer at diagnosis was also noted for other major sites including: lung, trachea and bronchus; colon and rectum; and prostate cancers. Trends toward an earlier stage of cancer may result from patient and physician education, local practice patterns, as well as proper use of screening programs. Information on such trends from hospital tumor registries may be helpful in the appropriate and efficient allocation of local health care resources.