Avascular necrosis of the hip is a serious clinical problem encountered by primary care physicians. It requires early detection for proper management and treatment. The clinician should be aware of the imaging modalities available for evaluation of patients with suspected avascular necrosis. Traditional studies include plain-film radiography, computed tomography, and planar bone scintigraphy. Magnetic resonance imaging and single-photon emission computed tomography bone scanning have been developed to such an extent that they are now the most sensitive indicators of early avascular necrosis. The authors review currently available imaging modalities and provide a practical approach to the assessment of patients with suspected avascular necrosis of the hip.