The radiologic manifestations of Reiter disease in 56 patients are described. Although the findings are often nonspecific, certain features are distinctive, particularly when present in combination. These include subtle periosteal bone apposition at bony prominences, the infrequency of regional panarthritis and hip and shoulder involvement, the tendency for destructive arthritis to be confined to small joints, particularly in the feet, and a typically "discontinuous" spondylitis characterized by eccentric, laterally positioned vertebral hyperostoses which tend to bridge around the contigous disk. Attention is drawn to similar hyperostoses which occur above the true sacroiliac joints. The significance of these features, particularly in terms of differential diagnosis, is discussed.