Non-adherence to therapy is associated with impaired outcome in solid organ allograft recipients. Outcome data are limited after lung transplantation. In a single-center cohort study, adherence was assessed in 427 patients undergoing lung transplantation from 2010 to 2013. Objective criteria of adherence were judged by health care workers on every visit on a five item Likert scale including trough level monitoring, home spirometry and contact with an overall rating of adherence between 0 and 100%. Cut-off values for good vs. suboptimal adherence were defined retrospectively. Primary outcome was allograft survival, secondary outcomes were patient survival, prevalence of chronic lung allograft dysfunction, hospitalizations, renal function and quality of life. Follow-up ended on 31st December 2018. Median adherence was 86% on 6,623 visits, this cut-off was used as a discriminator between good and suboptimal adherers. Patients with good adherence within the first three years showed better 5-year allograft (74% vs. 60%, p = 0.003) and patient survival (79% vs. 64%, p<0.001) and lower prevalence of chronic allograft dysfunction (33% vs. 45%, p = 0.011) after 5 years compared to patients with suboptimal adherence. A multidimensional adherence score proved to be a simple tool to assess adherence in clinical practice. Suboptimal adherence was associated with impaired outcome in lung transplant patients.