Introduction: this paper describes the initial construction and validation of an instument used to evaluate the capacity of self-care in patients with hypertension. The instrument is based on Dorothea Orem's Theory of Self-Care and is comprised of 17 items grouped into three dimensions: fundamental capacities; power components; and capacity of self-care management. Methods: the instument was administered to 159 people with hypertension. Construct validity was established using factorial analysis and internal hypertension. Construct validity was established using factorial analysis and internal consistency was determined by the Cronbach alpha statistical test. Results: the instrument showed a Cronbach alpha of 0.75, which is considered appropiate, even though the results of the factor analysis showed that the dimensions proposed by the authors did not meet the factors obtained by the extraction method of principal components. Conclusion: findings show that the instument could be used as a nursing evaluation tool. The instument can help identify the self-care management capacity of patients wit hypertension as well as assist in the creation of individual patient care plans. It is important, however, to continue the validation process since the empirical evidence supports the general assessment of the construct but not the dimensions as proposed in the model by Dorothea Orem.