OBJECTIVE To determine the disruption of low-molecular-weight aminothiols (LMWTs: cysteine, cysteinylglycine, homocysteine, and glutathione) homeostasis in blood plasma during the acute and early subacute stages after ischemic stroke. METHODS We admitted 41 patients with primary large-artery atherosclerosis and cardioembolic stroke in the carotid arteries within the first 6-24 h from the moment of neurologic symptoms development. We included 31 patients with chronic cerebral ischemia in the control group. Total LMWT levels and their reduced forms were measured in blood plasma on the 1st, 3rd, 7th, and 15th days after stroke. RESULTS Our study demonstrated a decrease of cysteine and cysteinylglycine reduced forms and an increase of total glutathione and cysteine levels. There were no differences in LMWT levels among stroke subtypes (large-artery atherosclerosis and cardioembolic stroke). The decrease (or increase) in GSH and Hcy redox status on the 3rd day after stroke was associated with severe neurological deficit. Total Hcy (1st day), Cys (3rd day) and CG(7th day) levels were associated with the size of cerebral infarction area. Logistic regression analysis indicated that reduced homocysteine, total cysteinylglycine levels, and cysteine redox status at admission were predictive factors for ischemic stroke occurrence with a probability of 86.2% (p < 0.001). CONCLUSIONS LMWTs may indicate the severity of neurological deficit and the size of the cerebral infarct, and their complex determination can be of diagnostic importance both at an early stage of ischemic stroke development and during its monitoring.