Spontaneous Achilles' tendon rupture associated with systemic lupus erythematosus (SLE) is rare complication in literature review. We encountered two patients with neglected spontaneous ruptures of Achilles' tendons who had been on corticosteroid therapy to treat SLE. The ages of these patients were 43 and 49 years, and both were women. One of them was a case of bilateral Achilles' tendons rerupture. Achilles' tendons of both patients were reconstructed by surgery because of delay in their diagnosis. Histological section of the both ruptured Achilles' tendon revealed fibrotic scar tissue and little existence of inflammatory change. We concluded that careful diagnosis, surgical suture, and careful treatment after operation are necessary for Achilles' tendon rupture in those patients with SLE.