Background Spontaneous isolated dissection of the superior mesenteric artery (SIDSMA) is a rare and potentially fatal disease. Several therapeutic options are available, including conservative therapy, endovascular repair, and open surgery. Herein, we report our experiences in the treatment of SIDSMA. Methods Between February 2009 and June 2013, 17 patients were diagnosed as having SIDSMA. We retrospectively reviewed and analyzed their clinical characteristics, medical history, risk factors, symptoms, diagnostic imaging modality, treatment, and outcome. The lesions were categorized according to the modified Sakamoto's classification. If no evidence of bowel necrosis or arterial rupture was present in the patients with symptomatic SIDSMA, we first performed conservative therapy, even if the patients had abdominal pain. Results The subjects included 15 men and 2 women, with a median age of 62.8 years. Eight patients were symptomatic and 9 were asymptomatic. Conservative therapy included the use of antithrombotic agents in 3 patients but not in 5 patients. During the follow-up period (mean, 21.1 months), all the patients were discharged without any significant complications, and none of the patients showed the progression of the dissection on follow-up computed tomography angiography examinations. Conclusions Conservative therapy without antithrombotic agents should be the primary treatment for SIDSMA. Endovascular repair for SIDSMA is associated with several risks, thus the procedure might occasionally be useful and necessary.