Background: Anti-tumor necrosis factor (anti-TNF) adherence is suboptimal. ava (R), a reusable electromechanical self-injection device (e-Device) developed for certolizumab pegol (CZP) administration, aims to overcome some barriers to increase adherence. This study evaluates patient experience of the e-Device and its training materials and determines patient device preference. Methods: CZP-treated patients were recruited from the Netherlands, Denmark and Sweden. Patients completed a pre-injection Assessment of Self-Injection (ASI) questionnaire investigating self-injection perception. After training, patients administered 3 consecutive self-injections using the e-Device, patient experience of each was assessed using the post-injection ASI. An additional questionnaire evaluated training materials. After Injection 3, patients indicated their preference: the e-Device or their previous device. Results: 59 patients participated; most rated the e-Device highly for satisfaction, self-confidence and ease of use. The (negative) feelings and pain and skin reactions domains had low ratings. Post-injection ASI domain scores were similar following each of the 3 e-Device injections. Training materials were rated highly (video: 8.4/10; step-by-step guide: 8.4/10). 57.1% (32/56) patients preferred the e-Device over their previous self-injection device. Conclusions: Patients were satisfied with the e-Device and most preferred it over other self-injection devices. By improving patient experience, the e-Device may help increase medication adherence.