The aim of this work was to compare the potential of computed tomography angiography (CTA) with that of digital subtraction angiography (DSA) in vascular mapping of the external carotid artery (ECA) branches for planning of microvascular reconstructions of the mandible with osteomyocutaneous flaps. In 15 patients CTA and DSA were performed prior to surgery. Selective common carotid angiograms were acquired in two projection for both sides of the neck. Sixteen-slice spiral computed tomography was performed with a dual-phase protocol, using the arterial phase images for 3D CTA reconstruction. Thin-slab maximum intensity projections and volume rendering were employed for postprocessing of CTA data. The detectability of the different ECA branches in CTA and DSA was evaluated by two examiners. No statistically significant differences between CTA and DSA (p=0.097) were found for identifying branches relevant for microsurgery. DSA was superior to CTA if more peripheral ECA branches were included (P=0.030). CTA proved to be a promising alternative to DSA in vascular mapping for planning of microvascular reconstruction of the mandible.