OBJECTIVE: To compare clinical and laboratory data obtained from patients with primary Antiphospholipid Syndrome (pAPS) with and without Thrombotic Microangiopathy (TMA). PATIENTS AND METHODS: A cross-sectional study with 66 (83.3% female) pAPS patients was performed. Demographic, clinical, drug use, antiphospholipid antibodies data were evaluated. Patients were subdivided into one of two groups: pAPS with TMA and pAPS without TMA and were compared. RESULTS: In this sample, 5/66 (7.6%) of patients had TMA. Primary APS with TMA group exhibited a higher frequency of arterial events (100% vs. 54.1%, p=0.02), stroke (100% vs. 32.8%, p=0.001) and a lower frequency of deep venous thrombosis (0 vs. 68.9%, p=0.0009) compared to the patients without TMA. Analysis of therapy used in these patients showed a higher frequency of current (40% vs. 6.6%, p=0.0006) and previous glucocorticoid use (80% vs. 36%, p=0.0007) and statin use (50% vs. 22.9%, p=0.037) in the first group. The two groups exhibited no differences in the frequency of positive autoantibodies, except for higher IgG anticardiolipin titers (86 ± 52 vs. 34.5 ± 39 GPL, p=0.003). CONCLUSIONS: Patients with pAPS and TMA have distinct clinical and laboratory spectra from those without TMA, that is characterized by an increased frequency of arterial events, stroke, and higher titers of IgG anticardiolipin; they have deep venous thrombosis less frequently.