PURPOSE: To determine the effect of coracoacromial ligament (CAL) resection and subacromial decompression (SAD)/acromioplasty on humeral head translation under anterosuperior and superior loading in a cadaveric model with an intact rotator cuff. METHODS: Six cadaveric shoulders were tested in the intact state, following CAL resection and following SAD. RESULTS: Excision of the CAL led to a significant increase in anterosuperior humeral translation of 2.1 mm (17%). SAD led to a significant increase in superior humeral translation of 2.5 mm (28%). CONCLUSIONS: The results of this cadaveric study showed that resection of the CAL led to a 2.1-mm increase in anterosuperior translation and that SAD led to a 2.5-mm increase in superior translation. CLINICAL RELEVANCE: CAL resection and SAD are common surgical procedures, which may lead to increases in anterosuperior and superior glenohumeral instability.