Nontraditional settings (NTS) are increasingly utilized for adult vaccination but concerns exist about their safety. We conducted this analysis of 542,445 persons vaccinated at an NTS in Minnesota to assess the safety of influenza vaccination in NTS. A total of 112 adverse events (AEs) were reported, 95 immediate and 17 late. Most AEs were mild and resolved within several minutes. 63 persons (.01%) had a vasovagal reaction to vaccination and 22 (.004%) reported an injection site problem. Immediate hypersensitivity reactions were very rare with only 10 (.002%) vaccine recipients having an immediate reaction for which epinephrine was required. Fifteen (.003%) individuals required evaluation in an emergency room or physician's office because of an AE. No deaths were reported. We conclude that influenza vaccine administration in mass vaccination clinics is safe and adverse events after influenza vaccination in NTS are extremely low.