INTRODUCTION Local coverage determinations (LCDs) are local decisions that regulate healthcare coverage. We evaluated the impact of LCDs as well as patient, tumor, and market characteristics on the adoption of stereotactic body radiation therapy (SBRT) for prostate cancer. METHODS Using Surveillance, Epidemiology, and End Results (SEER)-Medicare, we identified men treated with SBRT, intensity-modulated radiotherapy (IMRT), and robotic prostatectomy. We compared demographics, clinical characteristics, and market factors among these three treatments. Our primary exposure was LCD policy; using the Medicare Coverage Database, we categorized LCDs as favorable (SBRT covered), neutral (SBRT covered in the context of a clinical trial or registry), unfavorable (SBRT not covered), or absent (i.e., SBRT not governed by an LCD at the time of treatment). We fit a multivariable multinomial logistic regression model and generated predicted probabilities to examine the relation between LCDs and SBRT. RESULTS During this early period of SBRT adoption, IMRT was the most common of the three treatments followed by robotic prostatectomy and then SBRT. SBRT use was high when governed by favorable and neutral LCDs and lowest when governed by unfavorable LCDs. Compared with favorable LCDs, areas where LCDs were absent were associated with higher SBRT use compared with IMRT (odds ratio [OR] 1.56; 95%CI, 1.07-2.25) and robotic prostatectomy (OR 1.84; 95%CI, 1.25-2.69). CONCLUSIONS When present, LCDs appear to regulate early SBRT adoption, but, when absent, are associated with increased SBRT use. Although SBRT use was uncommon, it varied across a wide range of patient, tumor, and market characteristics.