Objective. To reveal relationships between the level of interleukins IL-1β and IL-4 and platelet aggregation (PA) in patients with ischemic stroke (IS). Material and methods. A prospective clinical cohort study includes 108 IS patients. The level of IL-1β and IL-4 in blood serum was determined by enzyme immunoassay. The study of PA was performed using nephelometric method in the very early (first 24 hours of hospitalization) and early (7th day of hospitalization) stages. Results and conclusion. In the very early stage of IS, significant PA disorders are accompanied by the increased IL-1β synthesis. In the early stage, decreased PA is accompanied by the decreased IL-1β synthesis and increased IL-4 synthesis. The decrease in the pro-inflammatory interleukin IL-1β level is accompanied by the increase in the anti-inflammatory interleukin IL-4. Conclusion. There is a mutual relationship between platelet activation, aggregation, degranulation, and interleukin synthesis, namely the lysis of aggregated platelets is accompanied by the expression of pro-inflammatory interleukin IL-1β. The positive correlation between PA and IL-1β allows us to conclude that interleukin IL-1β plays a neurodestructive role in the lesion-protection process while the negative correlation between PA and IL-4 indicates a neuroprotective role of the latter.