Pulmonary hypertension is a hemodynamic state defined by a mean pulmonary arterial pressure >20 mmHg and a pulmonary vascular resistance ≥3 WU, subdivided into 5 groups. Chronic Thromboembolic Pulmonary Hypertension (CTEPH) corresponds to group 4. The antiphospholipid syndrome is one of the most associated thrombophilia, with a prevalence of CTEPH of 2%-50%. A case-control study was conducted where data from the Right Cardiac Catheterization Registry of the PH Clinic were collected, with a diagnosis of CTEPH in patients aged 18-60 years and any sex. Antiphospholipid Syndrome (APLS) patients were separated from those with only CTEPH. It was developed in a statistical analysis based on frequencies, means, and standard deviation. The variables were evaluated using the Kolmogorov-Smirnov, Student's T, Mann-Whitney U, and Chi-Square tests with a 95% confidence interval. A total of 12 patients with APLS diagnosis and 30 without it were identified. The comparison between both groups shows that the patients with APLS were younger (38 ± 14.35 vs 51.63 ± 15.02 years, P 0.010) and had a significant association with autoimmune diseases (25% vs 0%, P 0.003). The patients diagnosed with APLS were primarily men (7 vs 5), and no statistically significant difference was found between laboratory and hemodynamic parameters. Patients diagnosed with CTEPH and APLS are mainly male, younger mean age, and have a greater significant association with autoimmune diseases than patients with CTEPH.