Various heavy metals have been known for causing ischemic stroke. In order to describe the causative relationship between the blood levels of various heavy metals and stroke patients, 116 patients with stroke and 111 patients without stroke were selected from one Oriental medical hospital in Wonju, Korea. Total of 9 kinds of metals such as As, Cd, Co, Cu, Hg, Mn, Ni, Pb, and Zn were analyzed in blood from patients with and without stroke. There were no significant differences in the means of metal concentrations between the stroke and nonstroke patients except for the mean of Co concentration. In the case of Co, the means for stroke and non-stroke patients were 0.44 ug/l and 0.40 ug/l showing a significant difference at the level of p-value=0.05. The odds ratios for each metal ranged from 0.96 to 2.86. Most odds ratios were not significant but the odds ratio for Co, $2.86{pm}1.49$ was significant, indicating that Co increases the risk of stroke by 2.86 times. In order to identify the specific risk level of stroke increased by a multiple interaction of metals, regression coefficients and odds ratio for a pair or multiple pair of metals were reanalyzed. However, all of regression coefficients and odds ratios were not significant. In conclusion, Co showed the significant level in blood from patients with stroke. In addition, the odds ratio of stroke was significantly different from other metals. Thus, it is considered that Co among various metals analyzed in this study is the important metal for increasing the risk of stroke.