The present study objective is evaluate Adalimumab efficacy versus Azathioprine efficacy on prevention of endoscopic recurrence (Rutgeerts Index= 2b, 3 or 4) in Crohn´s Disease patients after 52 weeks of treatment.

Inclusion Criteria:

• Age ≥ 18 years of age at the time of signing informed consent.
• Patients with Crohn's disease who have undergone an ileocecal/ileocolic resection (L1 or L3). The study and the treatment must be initiated within the two first weeks after the resection (+/- 5 days).
• Patients with surgical reconstruction by ileocolic anastomosis.
• Women of childbearing age must not be breastfeeding and must have a negative urine pregnancy test and must agree to use contraceptive methods with a <1% failure rate (e.g., sexual abstinence, oral contraceptives, double barrier methods, intrauterine devices), unless they only have one partner who is sterile.
• Patients who have signed and dated the informed consent form before performing any specific screening study procedure.

Exclusion Criteria:

• Resection that requieres Temporal ileostomy.
• Urgency resection which doesn´t permit the initial assessment protocol completion.
• Resection due to inactive short indolent stenosis (<10 cm).
• Resection with mucosal macroscopic residual disease in anastomosis.
• Previous intolerance or adverse reaction (moderate or severe) to adalimumab or azathioprine.
• Any contraindications or unwillingness to perform the scheduled colonoscopies or resonances.
• Contraindications to Adalimumab treatment, among which the following are included: active tuberculosis, severe infections such as sepsis or opportunistic infections, moderate or severe heart failure (NYHA class III or IV), central nervous system demyelinating diseases, history of malignant neoplasm or autoimmune diseases.
• Severe associated Extraintestinal manifestations.
• Previous postoperative recurrence prevention treatments with adalimumab, asathiprine o mercaptopurine which resulted in failure.
• Any other disease or patient condition that according to investigator criteria, inadequates patient´s participation in the study.