We evaluated the effects of adalimumab maintenance therapy on health-related quality of life (HRQOL) in patients with moderate to severe Crohn's disease. In a Phase III, randomized, double-blind clinical trial (CHARM) of moderate to severe Crohn's disease patients, HRQOL outcomes were compared between the adalimumab maintenance treatment groups (every other week and weekly injection) and the adalimumab induction-only group. The Zung Self-Rating Depression Scale, functional assessment of chronic illness therapy (FACIT)-Fatigue, visual analog pain scales, Inflammatory Bowel Disease questionnaire (IBDQ), and Medical Outcomes Study 36-item Short Form Health Survey (SF-36) were analyzed for 499 randomized responders (a decrease of > or =70 points from baseline in the Crohn's Disease Activity Index CDAI) at baseline and weeks 4, 12, 26, and 56. CHARM patients' HRQOL was substantially impaired at baseline. Following a 4-week adalimumab induction therapy, patients experienced statistically significant improvements in all HRQOL measures (P < 0.0001). Compared with patients who were assigned to placebo after induction therapy, patients who continued adalimumab at 40 mg every other week maintenance therapy reported less depression (P < 0.01), fewer fatigue symptoms (P < 0.001), greater improvements in the IBDQ (P < 0.05), greater SF-36 physical component summary scores (P < 0.05), and less abdominal pain (P < 0.05) from weeks 12 to 56. They also had greater SF-36 mental component summary scores at week 56 (P < 0.05). Patients who continued adalimumab at 40-mg weekly maintenance therapy reported less depression and fewer fatigue symptoms at week 56, greater improvement in IBDQ, and less abdominal pain from weeks 12 to 56 (all P < 0.05 vs. placebo). Adalimumab maintenance therapy provided sustained improvements in HRQOL for patients with moderate to severe Crohn's disease through week 56.