Five-factor personality was examined as an element of self-report diabetic control accuracy versus biomarker control (HbA1c) for 1474 diabetics in the 2006 and 2008 Health and Retirement Study. Correlations of extraversion and self-reported control (r = –.06, p < .01), and extraversion and HbA1c (r = .03, non-significant), were significantly different (t = 2.87, p < .01). Correlations of openness and self-reported control (r = –.05, p < .05), and openness and HbA1c (r = .01, non-significant), were significantly different (t = 1.91, p < .05). Associations were found between self-reported control and conscientiousness (r = –.05, p < .05), neuroticism (r = .04, p < .05), and openness (r = –.05, p < .05). Neuroticism was associated with self-reports that diabetes was worse (r = .07, p < .01). Other correlations and comparisons were non-significant.