The aim of this study was to determine the clinical outcomes of long-term anticoagulation therapy in patients with symptomatic spontaneous isolated dissection of the superior mesenteric artery (SIDSMA) and to evaluate whether conservative treatment with anticoagulation therapy is a safe and effective treatment modality for these patients.In this single center, observational cohort study, data from a prospectively recruiting symptomatic SIDSMA registry, including demographics, risk factors of interest, clinical characteristics and outcomes, and initial and follow-up computed tomography angiography (CTA) findings, were analyzed retrospectively. During an 8-year period, a total of 52 consecutive patients who underwent conservative treatment with the use of long-term anticoagulation were included in this study. Clinical symptoms resolved within 11 days in all except 4 patients (7.7%); 3 received endovascular treatment for persistent symptoms and 1 received surgical repair. The mean duration of anticoagulation therapy was 9 (range: 3-60) months. A follow-up CTA showed complete remodeling in 20 (41.7%) patients, and the mean diameter and the incidence of false lumen thrombosis were also decreased significantly. There was no anticoagulation therapy-related mortality or morbidity except 2 (4.2%) minor bleeding complications, and no symptomatic recurrence or aggravation of the dissection occurred during the mean follow-up period of 47.5 (range: 10-97) months. The present study showed that long-term anticoagulation therapy could result in a high rate of complete remodeling during the natural course of symptomatic SIDSMA. Conservative treatment with long-term anticoagulation therapy could be an optimal treatment strategy for symptomatic SIDSMA.