The purpose of this study is to determine whether the GI Endobarrier Liner is safe and effective.

Patients with obesity are at significantly greater risk of developing significant co-morbid complications, and are associated with an increased risk in all-cause mortality. The GI Endobarrier Liner represents a viable alternative to other short-term weight loss methods. It is a minimally invasive endoscopic procedure, which may allow patients to recover faster with less morbidity and mortality. This study is investigating the safety and efficacy of the GI Endobarrier Liner in patients who are candidates for bariatric surgery.

Inclusion Criteria:

• Age > 18 years and < 55 years - Male or Female
• BMI > 35 with significant comorbidities (i.e. hypertension, or hyperlipidemia, or diabetes) or > 40 BMI <60 (with or without a co-morbid condition)
• History of failure with nonsurgical weight loss methods
• Candidates for Roux-en-Y gastric bypass
• Willing to comply with trial requirements
• Signed an ICF
• Post-menopausal women with surgical sterilization or following any treatment or family planning and not planning to become pregnant during the course of the investigation

Exclusion Criteria:

• Treatment represents an unreasonable risk to the subject
• Pregnant or have intention of becoming pregnant for the duration of the trial
• Unresolved alcohol or drug addiction
• Receiving weight loss medications (prescription, over-the-counter, or herbal dietary medications)
• Previous gastrointestinal surgery that could affect the ability to place the EndoBarrier Liner or the function of the implant
• Active GERD
• Symptomatic kidney stones prior to implant
• Iron deficiency and/or iron deficiency anemia
• History of Inflammatory bowel disease or condition of the gastrointestinal tract, such as ulcers or Crohn's disease
• Symptomatic gallstones prior to implant
• Symptomatic coronary artery disease or pulmonary dysfunction
• Known infection at the time of implant
• History of congenital or acquired anomalies of the gastrointestinal tract such as atresias or stenoses
• Pancreatitis or other serious organic conditions
• Requiring prescription anticoagulation therapy
• Unable to discontinue NSAIDs (non-steroidal anti-inflammatory drugs) during the implant period
• Having or Family history of a known diagnosis or pre-existing symptoms of systemic lupus erythematosus, scleroderma or other autoimmune connective tissue disorder
• Participating in another ongoing investigational clinical trial
• Mentally retarded or emotionally unstable, or exhibits psychological characteristics requiring medication that affects appetite (i.e. tricyclic antidepressants and atypical antipsychotic medications) which, in the opinion of the Investigator, makes the subject a poor candidate for device placement or clinical trial
• Active Helicobacter pylori (Note: Subjects may be enrolled if they had a prior history of H. Pylori and were successfully treated)
• Having or a history of coagulopathy, upper gastro-intestinal bleeding conditions such as esophageal or gastric varices, congenital or acquired intestinal telangiectasia