Brain magnetic resonance imaging (MRI) was performed in 21 patients with systemic lupus erythematosus (SLE) with and without lupus anticoagulant (LAC), one lupus-like patient and 5 patients with primary antiphospholipid antibody syndrome. Thirteen patients had white matter focal brain lesions on MRI, 10 of whom had LAC (p = 0.03). We found no correlation between these lesions and neurologic manifestations, nor any clinical or serologic indices of activity of SLE. Our MRI lesions were similar to those described in multiple sclerosis and may indicate a similar pathologic process.