Gangliosides were extracted from cerebral tissue of reeler and normal mice, and analyzed by two-dimensional thin-layer chromatography at embryonic and postnatal ages. The ganglioside pattern changed substantially as development proceeded in the telencephalon of both reeler and normal mice, but was the same at any given age for both conditions, despite the marked histological differences between reeler and normal samples. These results indicate that abnormal ganglioside patterns do not result from the reeler mutation at early stages of brain development, and that the cell misalignment characteristic of the reeler phenotype involves molecules other than gangliosides.