The association of systemic lupus erythematosus (SLE) and hypothyroidism is uncommon, and concerns essentially the autoimmun thyroiditis. However, the coexistence SLE-primary hypothyroidism is exceptional. We report an observation of 25-old woman, who presents a clinical form of hypothyroidism, confirmed by hormonal tests, and which is associated to polyarthritis and proximal myopathy non ameliorated by opotherapy. The explorations conclude in SLE. A favourable evolution of muscular and articular signs is obtained with corticotherapy.