Although self-controlled breathing is a widely used relaxation technique, little is known about the role of respiratory sensations in breathing relaxation. We conducted field experiments in a group setting in which 137 male and 63 female participants (mean age = 21.8, SD = 8.8) were asked to progressively slow their breathing from 20 to 2 cycles/min (cpm) in steps of 2 cpm (20/18/16/14/12/10/8/6/4/2) for 15 min and to evaluate subjective comfort and the sensation of dyspnea at each pace. The following results were obtained. 1) The mean scores for subjective breathing comfort at the slow (2-4 cpm) and fast (16-20 cpm) paces were significantly lower than those at the typical resting breathing rates of healthy adults (12 and 14 cpm); there was an inverted U-shaped relationship between pace and subjective comfort (the upper half of Fig. 1). The subjective scores for dyspnea were significantly higher at the slow (2-8 cpm) and fast (18-20 cpm) paces than at the resting breathing rates, resulting in a U-shaped relationship between pace and sensation of dyspnea (the lower half of Fig. 1). 2) Each subject had a most-comfortable pace (CP) that combined the highest comfort and lowest sensation of dyspnea. Individual differences in CP were widely distributed between 2 and 18 cpm (Fig. 2). 3) At breathing rates above and below this CP, breathing comfort decreased and the sensation of dyspnea increased significantly (p < .05) (Fig. 3). These results suggest that breathing relaxation is determined primarily by respiratory sensations.