Antiphospholipid syndrome (APS) patients have high cardiovascular risk. Speckle-tracking echocardiography (STE) detects myocardial function. To evaluate the myocardial function in primary APS (PAPS) patients using two-dimensional echocardiography (2-D) obtaining values of left ventricle global longitudinal strain (GLS) by STE. Patients with PAPS, > 16 years, both genders, without signs and symptoms of heart disease were recruited and matched with healthy controls by age and gender. Demographic, clinical data, and cardiovascular risk factors were recorded. Images from the two-, three-, and four-chamber views were recorded and analyzed with STE and values of GLS. Descriptive and analytic statistics were applied. Thirty-eight PAPS patients and 21 controls were included. Age 46.7 ± 10, disease evolution 13.06 ± 6.69 years. Obesity and dyslipidemia were more frequent in PAPS patients in comparison with controls. Even though the proportion of obesity was greater in PAPS patients than in the control group, we did not find significant differences, neither in patients with/without metabolic syndrome. Regarding patients with and without obesity with lower GLS values, there were no differences either. Average GLS was lower in PAPS than in controls. Segments and myocardial regions showed lower values of myocardial deformation in PAPS patients than controls, including apical segments suggesting underlying heart disease. GLS is reduced in PAPS compared with healthy subjects. STE is a suitable method to detect cardiac affection in patients without apparent cardiac involvement. Studies with this technique to monitor progression of heart disease in PAPS are necessary.