This research project will investigate the effects of pramlintide (Symlin) given by continuous subcutaneous (under the skin) infusion throughout the day and night, along with meal doses similar to those injected during conventional pramlintide (Symlin) treatment, delivered using a second insulin pump, in subjects with inadequately controlled type I diabetes mellitus who are already using insulin pump therapy. Study participants will wear two pumps for a four month period, taking insulin in their usual manner and pramlintide (Symlin) in a similar basal/bolus fashion. Continuous glucose monitors will be worn on three occasions during the study to assess blood glucose responses to continuous pramlintide (Symlin) treatment.