Objective <p>To assess structure composition and psychometric properties of the Slovak version of the Hill-Bone Compliance to High Blood Pressure Therapy Scale (H-BCS).</p> Background <p>In patients with arterial hypertension (AH) and heart failure (HF), suboptimal adherence to treatment is associated with higher morbidity, mortality and increased healthcare costs. Therefore, regular monitoring of treatment adherence by objective tools is important.</p> Methods <p>In this cross-sectional validation study, 235 with AH and 122 patients with HF completed H-BCS. Confirmatory factor analysis, Pearson’s correlations and Cronbach’s alpha were used to assess construct validity respectively reliability.</p> Results <p>The results pointed to good fit for the three-factor solution of the Slovak versions of the H-BCS (Root Mean Square Error of Approximation = 0.062, Goodness-of-Fit Index = 0.936, Comparative Fit Index = 0.943, Tucker-Lewis Index = 0.924). Cronbach’s alpha of medication adherence domain was 0.855, adherence to diet 0.614, appointment keeping 0.475, and overall 0.846. In the total sample, correlations between H-BCS domains and systolic and diastolic blood pressure were not confirmed. However, correlation analysis in the sample of patients with AH revealed that a higher degree of non-adherence to medication and to diet was weakly associated with an increase in diastolic blood pressure and triacylglycerol level. Higher non-adherence associated with younger age, male sex and alcohol consumption.</p> Conclusion <p>The Slovak version of the H-BCS can be considered as valid and reliable for assessing medication adherence in clinical practice.</p>