These conference proceedings consist of 70 peer-reviewed technical papers representing subjects related to underground mine ventilation. All were presented at the 15th North American Mine Ventilation Symposium (NAMVS) from June 20, 2015 to June 25, 2015, held on the Virginia Tech campus in Blacksburg, Virginia. The included papers were selected by Symposium organizers because they reflect both present day critical challenges that underground mine ventilation professionals face as well as new innovative ideas that will propel the profession into the future. The content in the proceedings represents topics that include diesel exhaust and other contaminants in the mine atmosphere, dust in the underground mine environment, mine atmospheric monitoring, mine fans, mine fires, mine gases, mine heating and cooling, case studies, ventilation planning, and ventilation system design.