Cleno-humeral Joint is a ball and socket joint. It has the greatest range of movement among all the joints of the body. The greatest range of movement is inevitably accompanied by a considerable loss in stability. Thir-ty-three persons underwent Double Contrast CT arthrography of the shoulder for the evaluation of suspected shoulder derangement. We performed 62 shoulder arthrography (33 abnormal shoulders and 29 normal shoulders) and reviewed their findings retrospectively. They had recurrent shoulder dislocation (30 shoulders) or nonspecific shoulder pain (3 shoulders). Injury of the glenoid labrum was seen in 28 shoulders at double contrast CT arhrography. Among 28 eases oft he labral injury, labral detachment was seen in 15 cases, labral tear in 5 cases, and labral erosion in 8 cases. Double contrast CT arthrography also showed Hill-Sachs defect in 20 shoulders. The numbers of type 1, type 2, and type 3 capsulolabral attachment in 33 shoulder instability cases were 10, 16 and 7, respectivity, while, 16, 12 and 1 in 29 normal controls. Type 2 and 3 are more common in shoulder instability group than normal control group. Operation was done in 18 shoulders. Comparing with operation findings. the sensitivity of double contrast CT arthrography in the detection of Hill-Sachs defect was 100% with the specificity of 71% and the accuracy of 89%. The sensitivity, specificity, and accuracy of double contrast CT arthrography in the detection of labral injury were 94%, 100%, and 95% respectively. Double contrast CT arthrography is a minimally invasive and highly accurate technique for in the evaluation of glenohumeral instability.