Thirteen patients (all women) who developed systemic lupus erythematosus (SLE) after the age of 55 are reported. They constitute 18% of 71 consecutive SLE patients followed prospectively. Presenting features were predominantly cutaneous, neuropsychiatric and pulmonary. They had more interstitial lung disease and less arthritis than the younger patients. Eleven had positive antinuclear antibodies and only 4 had antibody to DNA. Strikingly, 12 had antibody to Ro(SSA) (accompanied by anti-La(SSB) in 8) compared to 36% in the younger group. SLE should be considered in older patients. Lung involvement is prominent. Antibodies to Ro and La are frequent and are a useful aid in diagnosis.