We designed and evaluated an ambulatory care intervention aimed at improving glycemic control and reducing hospitalizations in patients with insulin-dependent diabetes mellitus (IDDM). One hundred seventy-one youth with IDDM, ages 10-15, were assigned either to a Care Ambassador intervention (N = 89) or to standard care (N = 82). The intervention consisted of scheduling, confirming, and documenting medical follow-up for 24 months. During the study, the intervention group had more diabetes visits, 7.1 +/- 1.50 (mean +/- SD) Vs. 5.2 +/- 2.57 in the standard care group (P = 0.0001). In the at-risk subjects (baseline HbA1c 8.1%, N = 162), 50% of intervention subjects compared with 29% of standard care achieved HbA1c 8.6% while 17% of intervention subjects compared with 32% of standard care had values > 9.6% (P = 0.039). During follow-up, severe hypoglycemia and hospitalization/ER use occurred at half the rate in the intervention group compared with standard care. This specific, low-cost intervention aimed at increasing ambulatory medical visits in at-risk patients with diabetes improves metabolic outcomes and significantly reduces hospital/ER use.