Background: Changes in lifestyle in recent years have led to increase prevalence of cardiovascular diseases. On the other hand, longer life expectancy has resulted in higher numbers of demented patients including those with vascular dementia (VD). Since VD patients encounter many problems that decrease their quality of life, finding a marker for early detection of the disease is necessary. Measuring plasma levels of brain natriuretic peptide (BNP) might be helpful for early detection of VD. Methods: This cross-sectional study was conducted in Alzahra Hospital, Isfahan, Iran during 2011. We selected 2 groups of VD patients and ischemic stroke patients without dementia (ISwD). A group of healthy individuals was also included as the control group. Plasma levels of BNP were measured in all groups. Demographic data was also collected and recorded in a special checklist. Finally, data was analyzed by SPSS. Findings: Mean levels of BNP in the control, VD, and ISwD groups were 24.71 ± 13.2, 83.08 ± 9, and 51.57 ± 12.4 pg/ml, respectively. One way analysis of variance (ANOVA) revealed a significant difference between the three groups (P < 0.001). Conclusion: According to the results of this study, plasma level of BNP is a reliable marker for early detection and prediction of VD. This marker can also be used for identifying patients with history of cardiovascular diseases and stroke that are at the risk of VD. Keywords: Vascular dementia, Ischemic stroke, Brain natriuretic peptide