[Purpose] The present study attempted to identify the effect of olfactory stimulation on the balance ability of stroke patients. [Subjects] Thirty-three (33 males) stroke patients participated in the study. The stroke patients were divided into three groups: a black pepper oil (BPO) group (n=11), lavender oil (LVO) group (n=11), and distilled water (DW) group (n=11). [Methods] Two sessions (control trial/stimulus trial) of Romberg's test (eyes open 1 min/eyes closed 1 min) were conducted on a force platform to measure the data for the COP (center of pressure). Olfactory stimulation was provided at as a stimulus. [Results] With the eyes open, a statistically significant difference was found in average anterior posterior displacement (Ymean) and average medial lateral displacement (Xmean) among the three groups when comparing the groups before and after stimulation. The comparison between the eyes open and eyes closed conditions in each group showed a significant difference in the area of the 95% confidence ellipse (area) and Xmean of the BPO group and in the area of the LVO group (area, Xmean). [Conclusion] The findings indicate that the interaction of brain areas activated by the olfactory stimulation exerts an influence on the balance ability of stroke patients.