There have been many previously reported cases of adult-onset Still's disease (AOSD) which were successfully treated with tocilizumab (TCZ). However, the efficacy and safety of TCZ therapy for AOSD-associated macrophage activation syndrome (MAS), and the optimal duration of TCZ therapy, remain unclear. We herein report two cases of refractory AOSD, one of which was associated with MAS. These two patients were treated with TCZ, and the withdrawal of TCZ was planned according to the serum interleukin-6 level, which resulted in TCZ-free remission.