Objective: To determine the construct validity and reliability of the ‘‘Questionnaire to assess the adherence to treatment in patients with cardiovascular disease’’.Methods: This is a psychometric study. The selected sample included 250 patients diagnosed with cardiovascular disease and treated in a third-level-attention hospital institution in Neiva, Colombia during the first semester of 2016. The diverse research stages were chronologically developed as concept analysis, exploration, and construct confirmationResults: Through the concept analysis process, ‘‘self-efficacy’’ was established as a supporting theory with three theoretical components, six transversal thematic dimensions, and the essential attributes to the adherence to treatment, which were evidenced in the reformulation of the 38 ítems of the final version of the instrument. The sample was mainly constituted by persons older than 60 of age, which is a risk factor for hypertension and coronary problems. The exploratory factor analysis yielded 6 factors explaining 61.83% of the total variance. The multi-method and multi-treatment matrix demonstrated high intra-dimension correlations, and thus, the convergent validity of the instrument was evidenced. Cronbach alpha was 0.92 forthe total scale, and 0.80 for the scale dimensions.Conclusions: The present version of the instrument is valid and homogenous for the assessment of adherence to treatment in patients suffering from cardiovascular disease, and it is useful for the clinical practice and research.