The long-term results of outpatient management of subjects with newly diagnosed insulin-dependent diabetes mellitus (IDDM) are unknown. The longest follow-up described to date is for only one year, a time when most children with IDDM still make endogenous insulin. In this study, 41 young subjects with IDDM, treated and educated in the outpatient setting (1980 to 1984), were compared to a group of 80 similar subjects who received their initial education as hospital inpatients. Long-term glycemic control, as measured by longitudinal glycohemoglobin (HbA1) values was not different in the two groups (p greater than .05). We conclude that outpatient education and management of newly diagnosed subjects with IDDM is as safe and effective as inpatient treatment.