Objective: To test the effect of injection device (conventional syringe and needle versus needle-free injection device [NFID]) on the incidence of head and neck abscesses at slaughter. Materials and methods: Pigs raised under antibiotic-free (ABF) conditions (n=3424) were vaccinated first with combined Mycoflex and Circoflex (Boehringer Ingelheim Vetmedica Inc, St Joseph, Missouri) and second with ER Bac Plus (Pfizer Inc, Pfizer Animal Health, New York, New York), each via either conventional syringe and needle (Needle) or NFID. The first vaccination was given on the right side of the neck 1 day post weaning and the second on the left side of the neck 70 days post weaning. Four treatment groups were based on the vaccination injection methods: Needle-Needle; Needle-NFID; NFID-Needle; and NFID-NFID. Results: At slaughter, 3134 carcasses were evaluated for head and neck abscesses. The incidence of abscesses among the treatment groups did not differ (P>.05). More abscesses occurred on the right side of the neck (0.45%; P<.05) than on the left (0.13%). Overall abscess incidence (0.57%) was less than that typically observed in similarly sourced ABF pigs (2.51%) produced under field conditions and harvested at the same processing facility. Implications: Under the conditions of this study, incidence of head and neck abscesses at slaughter does not differ by injection device. Lower abscess incidence in study pigs than in ABF pigs under field conditions may be attributed to picking up small pigs for vaccination, frequent changing of needles, and not hurrying the vaccination process.