The present invention is a method for accessing the abdominal cavity of a patient in order to perform a medical procedure therein. In one embodiment the method includes the step of inserting a guide wire into the upper gastrointestinal tract, via a gastric opening in the gastric wall and an abdominal opening in the abdominal wall of the patient, the guide wire having a first end that extends from the mouth of the patient, and a second end that extends from the abdominal opening of the patient. The method further includes providing an access device in the form of an elongated sheath having a lumen therethrough, attaching the first end of the guide wire to the distal end of the elongated sheath, and pulling the second end of the guide wire to position the access device into the upper gastrointestinal tract, wherein the distal end of the access device extends into the abdominal cavity while the proximal end of the access device extends out of the mouth of the patient.