Abstract Films from 246 angiograms performed for acute trauma were reviewed for artifacts that mimic arterial pathology. The population studied was young (mean age 31.8 years), and preexisting arterial disease was uncommon. Thirty patients (12%) exhibited 35 artifactual abnormalities. Artifacts included stationary wave formation (15 patients), admixture in the leading edge of the contrast column (7 patients) or streaming from the inside aspect of an arterial curve (13 patients), Mach bands (8 patients), and abnormal densities caused by the mishandling of film (1 patient) or discharge of static electricity (1 patient). These artifacts have typical morphologic appearances and locations that allow differentiation from pathological processes that manifest as intraluminal filling defects or arterial wall irregularity.