Background: One of the main concerns in chronic diseases such as growth hormone (GH) deficiency is adherence to the treatment, which significantly affects treatment outcomes. Methods: This cross-sectional study was conducted among 169 GH recipient children (2-12 years) and teens (13-19 years) referred to a GH distributing teaching pharmacy. The eight-item Morisky Medication Adherence Scale (MMAS) and auto-compliance method were used for the assessment of patients' adherence to GH. The potential barriers to GH therapy adherence and medication persistence were also explored. Results: Based on the MMAS method, 56.7% of the children and 57.9% of the adolescent groups were adherent to GH therapy. Conversely, according to the auto-compliance method almost all the patients were adherent in the children (95.2%) and adolescent (95.5%) groups. Forgetting to take the injection or refill the prescription, being away from home, exhaustion from long-term injection, drug shortage and inaccessibility to the pharmacy were barriers found to be significantly associated with a low adherence in the children group. While in the adolescent group, forgetting to take the injection, painful injection, concern about longterm complications and exhaustion from long-term injection revealed a significant association with low adherence. Persistence with GH therapy was reported in 75.3% and 67% of children and adolescent patients, respectively.