We conducted a meta-analysis to acquire an understanding of the association between central nervous system cancer and occupational exposure to electric and magnetic fields. To explore sources of heterogeneity, study characteristics were scored and examined using regression analysis. An inverse-variance weighted pooling leads to a small overall increase in relative risk (10 to 20%) for the broad group of electrical occupations. One of the largest differences was lower relative risk for Scandinavian studies. Lower relative risks were also reported in cohort- and incidence-based studies. Findings were not sensitive to assumptions, including unpublished data, influence of individual studies, weighting schemes, and modeling. Whereas most studies present a small elevation in risk, there is considerable heterogeneity among the results.