The purpose of this study was to examine youths' knowledge of the hemoglobin A1c (HbA1c) test and glycemic control. Seventy youths (11-16 year olds) with type 1 diabetes were interviewed concerning their knowledge of the HbA1c test, health risks associated with particular HbA1c values, and their own glycemic goals. Results revealed that only 13% of youths accurately described the HbA1c test. Fewer correctly identified the HbA1c ranges for good, fair, and poor glycemic control. The majority of youths did not know the blood glucose values corresponding to specific HbA1c results. Only a small number of youth correctly estimated the short-term and long-term risks associated with maintenance of HbA1c of 7% and 12%. In this sample of mostly lower-income, minority youths with type 1 diabetes, there was a significant lack of knowledge concerning the meaning and implications of the HbA1c test. Findings suggest that interventions for this patient population should use the HbA1c test results to help young patients to better understand and set goals for their glycemic control.