This is a registry study to evaluate the long-term safety and effectiveness of adalimumab in pediatric patients with moderately to severely active CD who are treated as recommended in the local product label.

Inclusion Criteria:

• For a patient enrolling into the HUMIRA treatment group; A pediatric patient between the ages of 6 and 17 years inclusive at the time of enrollment, diagnosed with moderately to severely active CD who has been prescribed Humira therapy according to the routine clinical practice.
• For a patient enrolling into the immunosuppressant therapy treatment group; A pediatric patient between the ages of 6 and 17 years inclusive at the time of enrollment, diagnosed with moderately to severely active CD who has been prescribed azathioprine, 6-mercaptopurine or methotrexate.
• Parent or guardian; or patient (if 18 years of age or older at enrollment and rolling over from an AbbVie-sponsored investigational Pediatric CD investigation trial) has voluntarily signed and dated an Authorization for Use/Disclosure of Data (AUDD)/informed consent form (ICF) after the nature of the registry has been explained and the patient, patient's parent or legal guardian has had the opportunity to ask questions.

Exclusion Criteria:

• Patients should not be enrolled into the registry if they are currently being treated with any investigational agents or are receiving any investigational procedures.
• Patients should not be enrolled into the immunosuppressant therapy treatment group if they require ongoing treatment with approved biologic agents including HUMIRA.

Pediatric patients with moderately to severely active Crohn's Disease (CD) who have been prescribed HUMIRA according to the local label and pediatric patients being prescribed and treated with IMM (azathioprine, 6-mercaptopurine, or methotrexate). Patients being prescribed and treated with immunosuppressant therapy with no concurrent biologic use will be enrolled as a reference group.