Vagal tone, a measure of parasympathetic activity via the vagus nerve, is known to be associated with positive emotion because it promotes social engagement and self-soothing behavior. Heart rate variability (HRV), especially high frequency oscillation, is a direct measure of vagal tone, and has been used in previous studies to test the correlation between vagal tone and positive emotion. This study aims to determine if the two major oscillations of heart rate variability, high frequency (HF-HRV) and low frequency (LF-HRV) can predict pro-social behavior, which is classified as giving donations to charities. Baseline LF- and HF-HRV levels were recorded, and compared to how much each participant donated after watching several donation appeals by charities. Results showed there was no significant difference in either LF- or HF-HRV levels between donors and non-donors. A negative correlation was found between both LF and HF-HRV levels and donation behavior, contradicting research that predicts a positive correlation between the two variables. There was no significant effect of gender on donation amount. This research gives insight in to how physiological changes can affect psychological processes, such as emotional expression.