Objective: Zeneo(1) is a needle-free injection device. We performed a pharmacokinetic study to investigate the bioequivalence of methotrexate administered subcutaneously using either the needle-free injection device or a conventional needle and syringe. Research design and methods: This was a single-dose, open-label, laboratory-blind, randomized crossover study performed in adult healthy volunteers. Each participant received two methotrexate injections (each 25mg), one via needle-free injection device and one via conventional injection, with a 21-28day wash-out interval between dosing. For each participant, the administration site for both injections was either the abdomen or the thigh. Main outcome measures: The primary pharmacokinetic outcome parameters were AUC((0-t)) and C-max. Bioequivalence was assessed by standard criteria: whether 90% confidence intervals of geometric mean ratios for the two administration methods were within 80-125%. Results: Fifty-two individuals completed the study. Bioequivalence criteria were met for AUC((0-t)), for the overall analysis (both injection sites: 90% confidence interval: 99.4-103.1%), and for each injection site separately. Bioequivalence was similarly demonstrated with AUC((0-)). Bioequivalence criteria for C-max were fulfilled for abdominal administration but not for the overall analysis. Injection via the needle-free injection device was well tolerated.Limitations: Limitations include conducting the study in healthy volunteers and the relatively small subject number (albeit satisfactory for bioequivalence). Conclusions: This study shows that methotrexate injection via needle-free injection device is bioequivalent to a conventional needle and syringe in relation to AUC((0-t)) and AUC((0-)). Studies of needle-free injection device use in patients requiring methotrexate therapy are planned.