Deep slow breathing can increase vagal nerve activity, indexed by heart rate variability (HRV). HRV is also associated with better decision-making. This research examined the effects of two breathing patterns on HRV (Study 1) and on stress and decision-making performance (Study 2). In Study 1, 30 healthy people performed either a symmetric breathing pattern (equal ratio of inhaling/exhalation timing), a skewed pattern (exhalation longer than inhalation), or watched an emotionally neutral film (sham), following a baseline period. Both types of breathing patterns significantly increased time and frequency domain HRV parameters, while viewing the film did not. In Study 2, 56 students were randomized to perform 2鈥痬in of the skewed vagal breathing (experimental group) or to wait for 2鈥痬in (controls), before performing a 30-minute business challenging decision-making task with multiple choice answers. Stress levels were self-reported before and after the task. While controls reported elevations in stress levels, those in the experimental group did not. Importantly, participants in the experimental group provided a significantly higher percentage of correct answers than controls. These studies show that brief vagal breathing patterns reliably increase HRV and improve decision-making. Limitations, possible mechanisms and implications for business decision-making are discussed.