OBJECTIVE A multidisciplinary approach is required to treat critical limb ischemia. We determined the poor prognostic factors of ischemic ulcer healing after optimal arterial revascularization, and assessed the efficacy of the medication therapy using cilostazol, which is a selective inhibitor of phosphodiesterase 3. METHODS In this retrospective, single-center, cohort study, 129 limbs that underwent infrainguinal arterial revascularization for Rutherford class 5 critical limb ischemia were reviewed. The primary end point was the ulcer healing time after arterial revascularization. The secondary end point was the amputation-free survival rate. RESULTS Of the 129 limbs, endovascular therapy was performed in 69 limbs, and surgical reconstructive procedures were performed in 60 limbs for initial therapy. Complete ulcer healing was achieved in 95 limbs (74%). The median ulcer healing time was 90 days. In multivariate analysis, no cilostazol use significantly inhibited ulcer healing ( p = 0.0114). A white blood cell count >10,000 ( p = 0.0185), a major defect after debridement ( p = 0.0215), and endovascular therapy ( p = 0.0308) were significant poor prognostic factors for ulcer healing. Additionally, ischemic heart disease ( p < 0.0001), albumin levels <3 g/dl ( p = 0.0016), no cilostazol use ( p = 0.0078), and a major defect after debridement ( p = 0.0208) were significant poor prognostic factors for amputation-free survival rate. CONCLUSIONS Ulcer healing within 90 days after arterial revascularization is impaired by no cilostazol use, a white blood cell count >10,000, a major defect after debridement, and endovascular therapy. Furthermore, cilostazol improves amputation-free survival rate in patients with critical limb ischemia.