Twenty-six healthy young Caucasian males were defined into high hostile (Hi-Ho) group and low hostile (Lo-Ho) group assessed by Cook-Madley's Hostility (Ho) scale. Mental arithmetic task (MA) and forehead cold stimulus task (FCS) were loaded to both Hi-Ho and Lo-Ho groups. Electrocardiographic T-wave amplitude (TWA), heart rate (HR) and coefficient of variance of 100 R-R intervals (CVR-R) were measured continuously during MA and FCS task periods. Greater TWA attenuation was found in Hi-Ho group (p less than 0.05). Although no significant intergroup difference was represented in HR and CVR-R, HR increased significantly (p less than 0.01) in whole subjects and CVR-R was tend to be suppressed during MA period. In addition, comparison of these physiological responses were performed between Type-A and Type-B groups classified by Jenkins' Activity Survey Form-T (JAS-T). There was no significant difference in reactivity of TWA, HR and CVR-R to both two tasks between high and low Type-A scored groups. Previous data suggested that the TWA reactivity in Hi-Ho subjects to cognitive stress showed similar pattern in Type-A individuals. However, autonomic nervous interaction could not be clarified in Hi-Ho subjects. The differentiation of method for assessment of behavioral pattern was also discussed.