OBJECTIVES To assess the relationship between patients' expectations about and experiences with insulin therapy, and how they contribute to overall treatment satisfaction. METHODS The Expectations about Insulin Therapy (EAITQ) and the Experience with Insulin Therapy Questionnaires (EWITQ) were administered at baseline and endpoint, respectively, to insulin-naïve patients with type-2 diabetes in a randomized controlled trial comparing treatment algorithms for an inhaled insulin. Pearson correlation coefficients were calculated between EAITQ and EWITQ scores and patient characteristics and patient reported outcomes measures. Wilcoxon Signed Rank test was used to compare EAITQ and EWITQ item score distributions. Differences between EAITQ and EWITQ scores were calculated to categorize patients into three groups according to the extent to which their expectations about insulin therapy were met by experiences (i.e., not met, met, and exceeded). Oneway analysis of variance with Scheffe post-hoc tests was performed to detect differences in treatment satisfaction scores among the three groups. RESULTS EAITQ and EWITQ data were available for 240 patients (male: 61% male, age: 58 (mean) years old, diabetes duration: 10 years, HbA1c: 8.4%). More positive expectations were significantly associated with greater self-efficacy (p<0.01); more positive experiences were significantly associated with shorter diabetes duration, less symptom distress and greater well-being, self-efficacy, and treatment satisfaction (p<0.01). Overall, patients' experiences with insulin therapy were significantly more positive than their expectations, with 58% of patients' experiences exceeding expectations, 29% experiences met by expectations, and 13% experiences less than expectations. Post-hoc tests indicated that diabetes treatment satisfaction scores were significantly different among the three groups with higher scores associated with the exceeding of expectations by experiences. CONCLUSIONS Expectations may not independently impact treatment satisfaction, but their relationship with experiences significantly contributes to treatment satisfaction. The EAITQ and EWITQ may be useful tools for clinicians in identifying differences in expectations and experiences concerning insulin therapy.