Objective: Deep thigh veins, including the superficial femoral, superficial femoropopliteal, and profunda femoris veins, are versatile autogenous conduits for arterial reconstruction. Although late venous complications are unusual, deep vein harvest may induce severe venous hypertension and predispose the limb to acute compartment syndrome. The purpose of this study was to define the frequency of fasciotomy in patients undergoing deep vein harvest and to identify clinical predictors of the need for fasciotomy after deep vein harvest. Methods: Over 9 years, 162 patients underwent arterial reconstruction with deep vein harvested from 264 limbs. Indications for deep vein harvest included aortofemoral reconstruction in 127 patients, brachiocephalic arterial reconstruction in 22 patients, and visceral arterial reconstruction in 13 patients. Results: Fasciotomy was performed in 47 of 264 limbs (17.8%) after deep vein harvest. The prevalence of fasciotomy after deep vein harvest was 20.6% for patients requiring aortofemoral reconstruction, whereas no patients underwent fasciotomy after deep vein harvest for mesenteric or brachiocephalic arterial reconstruction (P = .0068). Fasciotomy was performed in 20.7% of limbs after complete deep vein harvest to a level below the adductor hiatus, but no fasciotomies were performed in patients undergoing subtotal deep vein harvest, ending above the adductor hiatus (P = .0023). The mean preoperative ankle-brachial index (ABI) was significantly lower in limbs requiring fasciotomy (ABI, 0.39 ± 0.05), compared with patients who did not require fasciotomy (ABI, 0.79 ± 0.02; P < .0001). Fasciotomy was performed in 76.0% of limbs undergoing concurrent ipsilateral greater saphenous vein (GSV) and deep vein harvest, compared with 11.7% of patients undergoing deep vein harvest alone (P < .0001). The mean volume of intraoperative fluid administered to patients requiring fasciotomy was almost 50% higher than the fluid resuscitation received by patients who did not require fasciotomy (9.6 ± 1.2 L vs 6.5 ± 0.6 L; P < .0001). Logistic regression analysis determined that lower preoperative ABI (odds ratio [OR], 60.1; 95% confidence interval [CI], 12.5-289.3; P < .0001) and concurrent harvest of the ipsilateral GSV (OR, 9.9; 95% CI, 3.1-31.3; P < .0001) were predictors of the need for fasciotomy. Conclusions: One in four patients undergoing deep vein harvest for aortofemoral reconstruction may be expected to develop acute compartment syndrome and require fasciotomy. The risk appears to be greatest in patients with severe lower extremity ischemia and in patients undergoing simultaneous GSV and deep vein harvest. Prophylactic fasciotomy may be appropriate in patients with both risk factors, but vigilance for the development of compartment syndrome after deep vein harvest is required in all patients undergoing deep vein harvest for aortofemoral reconstruction.