Objectives: It has been hypothesized that maternal characteristics and salivary cortisol may be related to the infant’s reactions to the stressful stimuli. The purpose of this study is to investigate the stress response pattern of pre- and post-heelstick of infants and to identify the factors from the mothers’ characteristics related to stress response of infants. Methods: Fifty two mothers and their healthy 57 infants (including 5 twins) participated in the study from July to December 2008. Stress response patterns in neonates were collected by measuring heart rate, oxygen saturation, and salivary cortisol. Mother’s demographic factors and awakening saliva were collected under a resting condition. Results: In infant, median level of heart rate (HR) was increased from 132.11 bpm to 140.36 bpm and the level of salivary cortisol was elevated from 0.4081 g/dL to 0.7019g/dL, while oxygen saturation was decreased from 97.46% to 94.97% experiencing discomforts. The change of infants’ heart rate was negatively correlated with gestational age (GA) (r = - 0.373, p = 0.010) whereas the change of infants’ salivary cortisol was positively correlated with maternal age (r = 0.294, p = 0.034). GA was the only independently significant predictor of HR responses (adjusted R2 = 0.124, p = 0.015). Influence of maternal age on infants’ salivary cortisol changes (adjusted R2 = 0.068, p = 0.036) was observed in a stepwise multiple regression. The level of maternal salivary cortisol was not correlated with other variables. Conclusions: HR, oxygen saturation, and salivary cortisol may be biomarkers of stress. These findings suggest that maternal age and gestational period can be influential factors of these variances. Therefore, it would be important to consider the demographic characteristics of mother-infant pairs to evaluate these influential factors.