Thrombosis can be associated with coronavirus disease 2019 infection. Computed tomography is essential for the diagnosis of pneumonia in these patients and conventionally contrast agents are required for the assessment of thrombus. In this study, we report a patient with coronavirus disease 2019 who was diagnosed with thrombosis using spectral noncontrast computed tomography with electron density imaging. The patient was a 76-year-old man who presented with a 2-day history of lower-leg pain. Tachycardia and atrial fibrillation were identified, with elevated D-dimer, N-terminal pro-B-type natriuretic peptide, creatine kinase, and C-reactive protein levels. Polymerase chain reaction testing for severe acute respiratory syndrome coronavirus-2 was positive. Conventional computed tomography showed pulmonary changes consistent with coronavirus disease 2019 and no changes in the aorta, but spectral computed tomography with electron density imaging of noncontrast computed tomography showed a thrombus in the right external iliac artery. Spectral computed tomography with electron density imaging provides more data compared with conventional computed tomography and has the potential to depict thrombus without the use of contrast media.