To participate in the study, you must have Type I diabetes mellitus and be taking insulin using an insulin pump, and have a hemoglobin A1c level between 7.0% and 10.0%. You will not be permitted to participate in the study if you have taken pramlintide (Symlin) during the previous three months. The study will consist of seven visits to the Study Center over a four-month period. Subjects will undergo meal tolerance testing at beginning and end of study period. Continuous blood glucose monitoring will be performed on three occasions during the study.