Diabetes mellitus with resistance to insulin administered subcutaneously or intramuscularly (DRIASM) is a rare and brittle form of Type I diabetes, found predominantly in young females and characterized by inadequate glycemic response to subcutaneous or intramuscular insulin administration. DRIASM leads to frequent ketoacidosis and obligatory hospitalization for administration of intravenous insulin. The use of a totally implantable infusion pump effected dramatic improvement in the treatment of five patients with this difficult form of diabetes. Frequency of clinical ketoacidosis was reduced from 37 episodes per year to 0.4 episodes per year (99%), and average inhospital days per month were reduced from 20.8 days to 2.2 days (89%) with a mean follow-up period of 14.4 months. Cost savings were approximately $10,000 per patient month. Quality of life was greatly improved for these individuals.