Introduction: This study aims to determine the prevalence and factors associated with non-adherence in maintenance treatment of adult patients diagnosed with bipolar disorder. Methods: Cross sectional study with 124 patients. Adherence to treatment was evaluated by the Morisky-Green Test. A structured questionnaire was applied. It included variables associated with demographics factors and factors related to the patient, illness, treatment, family, therapeutic relationship, and health system. The Global Impression Scale Modified for Bipolar Disorder (CGI-BPM) and Family Apgar were used as well. Results: The prevalence of non-adherence to maintenance drug treatment was 29.8%. It was greater in women (64.9%) than men (35.1%), although this difference was not statistically significant (p = 0.17). The factors statistically significant associated with non-adherence factors were: Increased severity of the disease (OR 1.9), history of non-adherence (39% P=0,001), negative perception of the psychiatrist (100%, P=0.001), less insight (87%, RP4.65), greater stigma (50%, RP 6.2), having no family member to remind taking the drug (73%, P=0.001). Conclusions: The prevalence was inside the range found in other studies. The statistically significant factors associated with non-adherence were: Severity of disease, history of non-compliance, stigma, no family support, poor insight, smoking habit, and negative perception of the psychiatrist.