Previous research showed that providing diabetic patients with information about diabetes is mostly insufficient for compliance. The purpose was to develop a new model for studying and promoting compliance in diabetes based on the theory of cognitive orientation (Kreitler & Kreitler), which assumes that in addition to knowledge it is necessary to consider the patient's goals, values and self image. We expected cognitive contents (beliefs) to be related to compliance, more in long-term than short-term patients. The subjects were 112 Type 2 diabetic patients. They were administered a Cognitive Orientation Questionnaire of Diabetic Compliance assessing cognitive contents in terms of four belief types (goals, norms, self and general) referring to relevant themes (e.g. discipline, reducing tensions). Compliance was assessed in terms of physical measures (HbA and number of complications) and behavioral measures based on information provided by the medical staff about glucose testing, taking medication, diet, exercise, independence, and follow-ups. The results showed that beliefs predicted (by discriminant analyses) the compliance measures more in long-terms and enabled describing the personality dynamics of compliers. The findings support a cognitive model of compliance. It predicts better in long-term than short-term diabetic patients.