BACKGROUND: Coexistence of multiple potential causes of cerebral infarct (MPCI) has been poorly studied. OBJECTIVE: To determine the risk factors, clinical findings, and topographical patterns of patients with at least 2 potential causes of cerebral infarct. DESIGN: Data analysis from a prospective acute stroke registry (the Lausanne Stroke Registry, Lausanne, Switzerland) in a community-based primary care center. RESULTS: Among 3525 patients with first-ever ischemic stroke consecutively admitted to a primary care stroke center, 250 patients (7%) had at least 2 MPCIs, with the following subgroups: large artery disease and a cardiac source of embolism (LAD + CSE) (43%), small artery disease and CSE (SAD + CSE) (34%), LAD + SAD (18%), and LAD + SAD + CSE (5%). Hypertension, cardiac ischemia, and a history of atrial fibrillation predominated in the LAD + SAD + CSE subgroup (P<.001), while cigarette smoking was more prevalent in the LAD + SAD subgroup (P<.05). A decreased level of consciousness and speech disorders were more common in the LAD + CSE subgroup (P<.001). Lacunar syndromes predominated in the LAD + SAD subgroup. Pure motor stroke was the most frequent lacunar syndrome in all subgroups, but sensory motor stroke predominated in the LAD + CSE subgroup (P<.05). The outcome at 1 month was worse in the LAD + CSE and SAD + CSE subgroups (P<.001). Other stroke characteristics and clinical features did not differ significantly between the 4 subgroups of patients with MPCI. CONCLUSIONS: Our findings suggest that MPCIs are uncommon. The most frequent association is LAD + CSE. Topographical patterns of stroke and clinical characteristics in patients with MPCI only rarely allow emphasis of a preeminent cause. Arch Neurol. 2000;57:1139-1144