Background/objective: Studies suggest that the neutrophil/lymphocyte ratio (NLR) may be a prognostic marker for different diseases with inflammatory components. This study aimed to quantify the NLR in individuals affected by different subtypes and severities of ischemic stroke and associated it with risk factors and treatment, and compared the results with data from healthy individuals. Methods: Clinical and laboratory data from medical records of patients over 18 years of age, victims of ischemic stroke, were collected. Data included leukocyte count and subtype, topography, risk factors, treatment and severity of stroke. For comparison, the number of leukocytes in healthy individuals was also quantified. NLR was determined by dividing the number of neutrophils by the number of lymphocytes. Results: A total of 218 patients were included, 194 stroke patients and 24 healthy individuals. Among all stroke patients, 45% had NLR values > 4 and 35% had values between 2 and 4; otherwise, 71% of healthy individuals had NRL < 2. The data also showed that the greater the severity of the stroke, measured by the NIHSS scale, the higher the NLR, at 24 and 72 h after the stroke. Among the stroke subtypes evaluated, the one with the lowest NLR values was small vessel stroke. Finally, the risk factors for stroke, its topography and treatment were not associated with NLR values. Conclusions: NLR is associated with stroke severity but does not correlate with stroke risk factors, topography, and treatment. The NLR may serve as a marker of stroke severity.