Background: Concurrent atherosclerosis (AS) in peripheral arteries may worsen the prognosis of ischemic cerebrovascular disease (ICVD) patients. Although cervicocephalic atherosclerotic burden (AB) has demonstrated strong risk stratification capabilities, whether peripheral arterial evaluation provides incremental prognostic value remains unclear. This study aimed to determine whether cervicocephalic-peripheral AB (CPAB) improves risk stratification in ICVD patients. Methods: This prospective cohort study consecutively included acute ICVD patients. AB scores for intracranial, cervical, renal, and lower extremity arteries were assigned as 0 (no stenosis), 1 (significant stenosis in one segment), or 2 (significant stenosis in >= 2 segments). The total score (range 0-8) was trisected into low, medium, and high CPAB levels. The primary endpoint was a composite of ischemic stroke, acute coronary syndrome, and vascular death. Model performance was evaluated using Harrell's C and Somers' D. Results: Among 403 patients (mean follow-up: 9.6 +/- 5.4 months), 41 primary endpoints occurred, and 21 (5.2%) were lost to follow-up. Of 382 patients analyzed, 30.6% had significant peripheral AS. Patients with concurrent peripheral-cervicocephalic AS had a higher risk of vascular events (p = 0.001) than those with single-territory AS. CPAB was independently associated with the primary endpoint (HR = 2.22, p < 0.001) and stroke recurrence (HR = 1.90, p = 0.013). While cervicocephalic AB also independently predicted outcomes, the CPAB-based multivariate Cox model had improved discriminative performance (Harrell's C = 0.678 vs. 0.653 for primary endpoint, p = 0.02; 0.646 vs. 0.634 for stroke recurrence, p = 0.03). Conclusions: Peripheral AS is common in ICVD patients and contributes independently to vascular risk. The CPAB score, which integrates atherosclerotic burden from both cervicocephalic and peripheral territories, could improve prognostic stratification compared to single-territory or cervicocephalic AB alone, supporting comprehensive multiterritorial AS assessment to guide risk-based management strategies.