Time trends in the incidence of glioma may reflect changes in the prevalence of environmental risk factors for glioma. We therefore investigated trends in the incidence of childhood and adult glioma in The Netherlands from 1989 to 2003. We used population-based incidence data from the Netherlands Cancer Registry. We calculated European standardised incidence rates for glioma, and stratified for age, gender and glioma subgroups. Changes in the incidence were estimated by calculating the Estimated Annual Percentage Change. Similar to other countries, the overall incidence of glioma was fairly stable in The Netherlands during the period 1989 to 2003, for both children and adults. In adult astrocytic glioma, a significantly increasing incidence of high-grade astrocytoma was balanced by simultaneous decreases of low-grade astrocytoma, astrocytoma with unknown malignancy grade and glioma of uncertain histology. Most of these time trends can be explained by improving detection and diagnostic precision. Stable incidence rates of adult and childhood glioma suggest that no major changes in environmental risk factors have occurred, which influenced the incidence of glioma in the studied period.