The primary purpose of this study was to determine if there were differences in trajectories of metabolic control between African American and White youth with type 1 diabetes in the first 5 yr after diagnosis. A secondary purpose was to investigate other sociodemographic variables that often covary with race/ethnicity such as number of parents in the home and family income to determine if they predicted trajectories of metabolic control in youth with diabetes over and above the effects of ethnicity. A convenience sample of 71 youth was recruited. Multilevel modeling was used to estimate the population trajectory and to investigate the contribution of other variables. Differences in metabolic control between African American and White youth began shortly after diagnosis and continued to accelerate well beyond the point of diagnosis. However, subsequent analysis showed that deterioration in metabolic control could equally well be explained by living in a single-parent household. At 24 months postdiagnosis, the metabolic control in youth from single-parent families worsened almost three times as fast as that in youth from two-parent families (0.11 vs. 0.04%/month). The difference in hemoglobin A1c level at 24 months was 1.34% (p = .007). Neither family income nor clinical variables such as child's age, Tanner stage, or body mass index was significant predictor of metabolic control. Diabetes care providers should consider developing targeted interventions such as parent social support resources or school-based youth monitoring programs for youth in single-parent families.