Each abdominal neuromere of a Drosophila embryo contains about 60 glial cells [Klämbt C, Goodman CS (1991): Glia 4:205-213 ; Ito et al. (1995): Roux's Arch Dev Biol, 204:284-307 ]. Among these, the midline and longitudinal glia are described to some detail. The midline glia are located dorsally in the nerve cord ensheathing the two segmental commissures. They are required for the proper establishment of commissures. The longitudinal glia, the A and B glia, and the segment boundary cells (SBC) are covering the longitudinal connectives. The longitudinal glia prefigure longitudinal axon paths and appear capable of regulating the expression of neuronal antigens. In the following we summarize the knowledge on the function of these glial cells.