We report a 29-year-old Japanese woman with disseminated intravascular coagulation (DIC) and adult onset Still's disease (AOSD). Her disease was refractory to high-dose glucocorticoids, two courses of steroid pulse therapy, and addition of cyclosporine (3.5 mg/kg/day). The serum interleukin-6 level was markedly elevated. Therefore, we administered an anti-interleukin-6 receptor antibody (tocilizumab, 8 mg/kg fortnightly), which dramatically improved her symptoms and the levels of acute-phase proteins. In addition, rapid tapering of the glucocorticoid dose was possible. Four months later, she was maintained on tocilizumab infusion once a month with low-dose steroid therapy. Cyclosporine is one of the first-line immunosuppressants for AOSD, especially when associated with DIC, hepatic failure, or hemophagocytic syndrome. In patients with cyclosporine-resistant AOSD, tocilizumab may be another useful option.