摘要:Purpose: Poor adherence to levothyroxine is a potential risk factor for treatment failure that ultimately leads to increased healthcare costs and serious health outcomes. This study aimed to investigate the correlation between illness perception and medication adherence among primary hypothyroidism patients. Patients and Methods: We conducted a cross-sectional survey among primary hypothyroidism patients who met the inclusion criteria in the Qassim region of Saudi Arabia using a questionnaire with demographic characteristics, clinical factors, the 12-Item Medication Adherence Scale, and the Brief Illness Perception Questionnaire (BIPQ). We included 400 patients in the analysis. Results: We found a significant positive correlation between BIPQ subscales – personal control, treatment control, and understanding – with all domains of the 12-Item Medication Adherence Scale. The other dimensions of BIPQ subscales did not significantly correlate with medication adherence. However, a high BIPQ overall score was significantly correlated with poor medication adherence. Conclusion: This study found a significant correlation between a high BIPQ overall score and poor medication adherence. This finding suggests the need to consider the emotional and cognitive representation of hypothyroidism in hypothyroid patients to improve their treatment adherence.