The study included 54 patients with glenohumeral instability. For every patient; Ultrasonography, MRI were done and intra-articular contrast injection in some cases (MRA) .The preliminary results have shown the role of sonography in monitoring of instability. Correlation between US and MRI and clinical findings may have a role in diagnosing glenohumeral instability. MR arthroghraphy is promisable in defining the type of instability