Diagnosis of adult pyogenic osteomyelitis is initiated on the basis of clinical exam; however, the presence and extent of disease can be most accurately assessed with imaging. The selection of an appropriate imaging technique is important to effectively characterize disease. The 2 most critical modalities for the evaluation of osteomyelitis are plain radiography and magnetic resonance imaging. Plain radiography remains the most appropriate initial examination, and it often yields the necessary information to guide management. Magnetic resonance imaging is particularly a useful modality for the assessment of osteomyelitis, because it provides exquisite soft tissue detail, accurately demarcates the extent of disease, and can identify the presence of abscess or devitalized tissue. A practical algorithm with emphasis on imaging selection in the setting of osteomyelitis relies on a multidisciplinary approach that incorporates the expertise of the clinician and the radiologist to develop the optimal treatment strategy for the patient.