A 30-year-old woman, diagnosed as having systemic lupus erythematosus at the age of 18, presented with excessive sleepiness and cataplectic attacks. Sleep laboratory findings were consistent with narcolepsy. To the best of our knowledge an association between these 2 diseases has never been reported. The unrelated course of narcolepsy and lupus symptoms in our patient suggests a lack of common pathogenetic mechanisms and this association is more likely explained by genetic factors.