This study used data from the California Cancer Registry to comprehensively examine first primary central nervous system tumors (PCNST) by the International Classification of Childhood Cancers (ICCC) diagnostic groups and to compare their incidence by age groups, sex, race/ethnicity, socioeconomic status and tumor behavior. The study period, 2001-2005, represents the first 5 years of benign PCNST data collection in the state. The age-adjusted incidence rates were 2.1 for malignant and 1.3 for benign per 100,000. Children younger than 5 years old had the highest incidence of malignant PCNST (2.6 per 100,000). Teens aged 15-19 had the highest incidence of benign PCNST (1.8 per 100,000). Age-specific incidence rates were nearly the same for Hispanics, non-Hispanic whites, and Asian/Pacific Islanders for malignant PCNST among children younger than 5 (2.6-2.7 per 100,000); non-Hispanic whites had the highest rates in the 5-14 year-old age group (2.5 per 100,000) and Asian/Pacific Islanders the highest among the 15-19 year old age group (2.3 per 100,000). We found no statistically significant differences in the incidence of malignant PCNST by race/ethnicity in any age group. Astrocytoma had the highest incidence for both malignant and benign histology in most age groups.