Thirty-eight patients with the primary Sjögren syndrome, 16 with active neuropsychiatric manifestations and 22 without clinical evidence of central nervous system involvement had magnetic resonance (MR) imaging. Eight patients had focal neurologic deficits (6 of these also had psychiatric, or cognitive dysfunction), and 8 had psychiatric or cognitive abnormalities alone. Magnetic resonance imaging showed abnormal results in 12 of 16 (75%; 95% CI, 48 to 93) patients with active central nervous system disease (67 focal lesions predominantly within the subcortical and periventricular white matter), and in 2 of 22 (9%; 95% CI, 1 to 29) patients without clinical evidence of central nervous system disease (P less than 0.0001). Seven of eight patients with focal neurologic deficits and 5 of 8 patients with psychiatric or cognitive dysfunction alone had abnormal results on MR imaging. Magnetic resonance imaging was more sensitive in the subgroup with focal deficits, (sensitivity, 88%; 95% CI, 44 to 97) than computerized axial tomography or cerebral angiography. Magnetic resonance imaging detects focal cerebral lesions in patients with the Sjögren syndrome and central nervous system involvement, including patients with psychiatric and cognitive dysfunction alone.