THE CONDITION referred to as transient synovitis of the hip joint is not infrequently encountered in clinical practice. We, in the past year have seen six cases in our clinical and hospital material. The medical literature, however, has very few reports of this entity, and the radiological literature contained none until a recent article by Drey presented some of the roentgen findings in a case which he had the opportunity of following. We are presenting two illustrative cases which demonstrate the salient features of this disease. Belmonte, Bradford and Lovett, Butler, Finder, and Miller have contributed papers on the subject. Lucas, in 1948, and Edwards, in 1952, reviewed the entity of transient synovitis of the hip joint and their valuable contributions summarized the present knowledge of the subject. Other names by which this condition has been identified are transitory coxitis, coxitis serosa seu simplex, coxitis fugitive, and transitory arthritis of