There is increasing recognition that the patient education and care provided to young adults with chronic physical illnesses, including type 1 diabetes, is inattentive to the complex developmental issues facing the older adolescent transitioning into the young adult period [Pediatrics 110 (2002) 1307]. In this paper, we present a clinical perspective on the challenge of improving diabetes education and care during the young adult period focusing on the importance of the developmental changes-cognitive, social, emotional, educational, and familial-that occur during this transitional stage of life. This developmental perspective on young adulthood provides a conceptual framework to better understand the young adult's "readiness" for engagement in intensive medical therapy. We review factors such as the timing and context of diabetes care and education that may be important determinants of young adults' ultimate success in becoming independent managers of their health care during this difficult transition. Developmentally-based practice principles for the young adult period are presented which include: assessing the patient's expectation at transition, building the relationship, working with families, assessing barriers to care, and formulating treatment plans and goals.