Objective To describe the health literacy of parents of high-risk adolescents with insulin dependent diabetes and to examine the relation of parent's health literacy with treatment adherence. Methods Participants were 93 adolescents in poor metabolic control diagnosed with insulin dependent diabetes and their primary caregivers. Results All parents had adequate health literacy as defined by the S-TOFHLA. Better parent reading comprehension scores were significantly related to family structure, race, and treatment regimen. Reading comprehension in turn significantly predicted adherence for adolescents on an intensive insulin regimen but not for those on conventional regimens. Conclusions Parents with low health literacy may struggle to help their children adhere to the increasingly complex diabetes regimens being used at present. Such families may benefit from more intensive diabetes education or different approaches to teaching diabetes management skills.