In summary, the newer technologies in radiology have allowed us to visualize more clearly the manifestation of joint disease in children. The presence of small erosions and cartilage damage can be seen much better with magnetic resonance imaging than with any other modality short of arthrography, a much more invasive examination. Joint effusion, although sometimes visualized with conventional radiography, is probably best recognized with ultrasound or magnetic resonance imaging, although it can be detected with computed tomography as well. For the evaluation of avascular necrosis that can be associated with steroid use in joint disease, bone scintigraphy is a simple, sensitive method. Magnetic resonance may be as or more sensitive and gives additional information as well. In the detection of change with time, conventional radiography probably will remain the standard as it is still the simplest, least expensive examination; however, it has many limitations in specific cases. Bone scintigraphy may be of value in selected cases. Although we have still not had enough experience with magnetic resonance imaging to use it as a way of evaluating progress of joint disease, it promises to be the most sensitive radiologic measure of evaluating progress as small anatomical changes can be detected within the cartilage, which cannot be done easily with other means.