The onset of systemic lupus erythematosus (SLE) is often marked by seemingly innocent musculoskeletal symptoms, and these may dominate its early course. Unless they are recognized, patients may go on for a long time with some rheumatic diagnosis until an acute febrile episode or visceral or cutaneous symptoms afford clues to the correct diagnosis. In the course of 7 years, 23 cases of SLE have been found among the patients attending the rheumatology service of a hospital for joint diseases. The musculoskeletal symptoms varied from patient to patient and from time to time, and resembled a variety of other rheumatic states. Two important diagnostic clues are the frequent remissions and exacerbations with few or no residuals, and the discrepancy between severe rheumatic symptoms and inconspicuous physical and roentgenographic changes.