Twin-roll casting (TRC) is a modern method of preparation of aluminum alloys. The distinctive feature of TRC is the combination of rapid metal solidification and subsequent plastic reduction in a single combined processing step. As a result of intensive heat extraction to the coolant via caster rolls, the melt solidifies and undergoes plastic reduction similar to the rolling process. However, some specific microstructural features of twin-roll cast strips, which restrict applications of this technology, are known. These are localized centre line segregation, surface and near-surface microsegregation and microstructural inhomogeneity. These features lead to the deterioration of mechanical properties of the strips, in particular strength, formability and corrosion resistance and can only be eliminated during a complex thermomechanical treatment. In the present contribution segregations in TRC Al-Mg-Sc-Zr alloy were studied by means of light optical microscopy, electron microscopy and 3D X-ray computer tomography. The spatial distribution was succesfully detected and morphology was described.