Antiphospholipid (Hughes') syndrome (APS) has not been reported in African-Americans (A-A) as frequently as in other ethnic groups. We describe eight A-A female patients with APS, including two cases of primary APS (PAPS), four with APS secondary to systemic lupus erythematosus (SLE), one with Sjögren's syndrome, and one with overlap connective tissue disease (CTD). Their mean age was 34 y (range 24-47 y). Patients were followed for a mean of 6 y (range 0.3-11 y). During follow up, both anticardiolipin (aCL) and anti-beta2glycoprotein-I (abeta2GPI) antibodies were measured in stored sera by enzyme-linked immunosorbent assay (ELISA). IgA was the most frequent isotype of aCL and abeta2GPI, and co-occurred with the IgM isotype in three of four patients with neurologic manifestations.