Characteristics of three databases--the Central Brain Tumor Registry of the United States (CBTRUS) database; the Surveillance, Epidemiology and End Results (SEER) database; and the National Cancer Data Base (NCDB)--containing information on primary brain tumors are discussed. The recently developed population-based CBTRUS database comprises incidence data on all primary brain tumors from 11 collaborating state registries; however, follow-up data are not available. SEER, the population-based gold standard for cancer data, collects incidence and follow-up data on malignant brain tumors only. While not population-based, the NCDB identifies newly diagnosed cases and conducts follow-up on all primary brain tumors from hospitals accredited by the American College of Surgeons. The NCDB is the largest of the three databases and also contains more complete information regarding treatment of these tumors than either the SEER or CBTRUS databases. Additional strengths and limitations of each of these are described, and their judicious use for supporting research, education, and health care planning is encouraged.