Cross-sectional imaging modalities including multidetector computed tomography (MDCT) and magnetic resonance imaging (MRI) are the diagnostic standard in detection, characterization, and staging of renal masses due to their high sensitivity and specificity. Currently, most renal masses are incidentally diagnosed by imaging for other medical reasons. Recent developments have improved image acquisition with high resolution, while simultaneously reducing radiation dose. CT imaging is the most accessible cross-sectional imaging method and is, therefore, the standard technique. MRI is indicated in patients who are allergic to intravenous CT contrast medium, in patients with renal insufficiency, or in younger patients. Further characterization of renal masses is possible with functional imaging including dual energy CT, perfusion CT, or diffusion-weighted MRI. Contrast-enhanced ultrasound allows detection of even subtle enhancement in hypovascular lesions with high sensitivity and can add valuable information to CT and MRI studies.