In this 12-week open-label, uncontrolled study, patients (n = 85; mean [SD] age 11.2 [3.95] years) were trained to use an injection device with an automatic needle insertion accessory (NordiFlex/NordiFlex PenMate: Novo Nordisk A/S, Bagsvaerd, Denmark) for growth hormone (GH) injection. The opinions of patients and the physicians/nurses who trained patients on device were recorded by questionnaire. Most (88.4%) patients reported that the device was "very easy/easy" to use. The majority (82.4%) of patients were "very satisfied/satisfied" with the device and 64% wished to continue its use. Device training instructions were reported as "very easy/easy" by 96.1% of physicians/nurses, and 65.8% of participants could use the device after ≤10-minute training. In this study, NordiFlex PenMate was well accepted by patients and medical staff. Patients had a high opinion of the device and over half wished to continue its use. High patient acceptance may facilitate treatment adherence optimizing treatment outcomes.