Objectives: Compared with all other patterns, isolated right colon ischemia has been found to be more associated with coronary artery disease and a poor prognosis. However, there has been no research on comparing isolated left side ischemic colitis (ILIC) and non-ILIC with vascular assessment. The aim of the present study was to evaluate the clinical and laboratory findings between these two different forms of ischemic colitis (IC). Methods: We retrospectively investigated differences in clinical features, course, and mesenteric vascular (superior mesenteric artery, SMA; inferior mesenteric artery, IMA) findings between ILIC and non-ILIC patients who were hospitalized at Kosin University Gospel Hospital from 2004 to 2010. Results: Our study population comprised 221 patients, all of whom met our entry criteria of biopsy-proven or -compatible IC. Of the 221 patients, 46 (20.8%) had non-ILIC. Congestive heart failure and hypercholesterolemia were more frequently observed in the non-ILIC group (P = 0.003 and P = 0.020, respectively). SMA atherosclerosis and SMA stenosis were more frequently observed in the non-ILIC group (P = 0.006 and P = 0.001, respectively). Recovery periods were longer in the non-ILIC group (P = 0.039), and mortality was lower in the ILIC group (6.9% vs. 17.3%, P = 0.026). Conclusions: ILIC has favorable outcomes compared with non-ILIC. Furthermore, non-ILIC showed a close relationship with SMA atherosclerosis and SMA stenosis, which should be investigated carefully in the clinical field.