BACKGROUND Ischemic ocular motor nerve palsies (IOMP) and lacunar brain infarcts share a similar pathological mechanism. The clinical characteristics of patients as well as the protective role of aspirin should therefore be similar in both conditions. METHODS The medical records of 107 consecutive patients with IOMP and 160 patients with lacunar cerebrovascular accidents (CVA) were reviewed and analyzed with respect to patient characteristics, vascular risk factors, and aspirin intake. The data on patients with and without aspirin were compared within each group as well as between both groups. RESULTS Hyperlipidemia, smoking, high carotid stenosis (>70%) and the presence of more than one vascular risk factor in an individual patient were found to be more common in patients with lacunar brain infarcts regardless of aspirin intake. Absence of vascular risk factors was encountered more in IOMP patients. The recurrence of lacunar CVA was significantly higher than recurrence of IOMP. A history of Bell's palsy was more common in IOMP patients than in patients with lacunar CVA. Within the IOMP group, the prevalence of vascular risk factors did not differ between the aspirin and non-aspirin group. Ischemic heart disease (IHD), CVA and recurrence were found more often in the aspirin group. Within the CVA group hypertension, IHD, cardiac arrhythmia and recurrence rate were more common in the aspirin group whereas smoking was found to be more common in the non-aspirin group of patients. CONCLUSIONS Arteriosclerosis is the main cause of lacunar CVA and IOMP. However, IOMP depends less on the presence of vascular risk factors than does lacunar CVA. Furthermore, aspirin - at least at low doses - does not seem to have a protective effect on either of these conditions, but more extensive prospective studies of homogeneous groups of patients are needed to clarify the preventive role of antiplatelet agents in IOMP.