OBJECTIVES: Patient reported Treatment Satisfaction instruments can be used to assess degree of acceptability and effectiveness of a treatment. For diabetes, this assessment can be helpful for guiding treatment decisions about the most optimal insulin therapy regimens for a given patient. Unfortunately, there are no instruments identified in the literature that assess the full spectrum of satisfaction issues with insulin therapies. Therefore, we undertook the development and validation of the comprehensive Insulin Treatment Satisfaction Questionnaire (ITSQ). METHOD: An original item pool was developed using data collected from five focus groups with insulin users, current literature and consultation with behavioral diabetes researchers. The initial questionnaire was tested in 170 diabetes patients from 3 large clinical centers in different regions of the US who were currently using a variety of insulin regimens. A confirmatory psychometric study in 402 insulin users was subsequently conducted. RESULTS: Item and scale analysis with IRT and factor analysis resulted in the identification of six subscales: Ease/Convenience, Interference, Lifestyle, Hypoglycemia, Glycemic control, and Insulin Delivery System. Cronbach alpha reliability ranged from .79 to .92, and 2-week test-retest reliability (n=35) ranged from 0.65 to 0.89. Convergent validity of the ITSQ was established in relation to several questionnaires, including the PAID, insulin self-efficacy and diabetes symptoms questionnaires. The ITSQ subscales discriminated significantly for A1c level, Type 1 vs. Type 2 diabetes, and global satisfaction. The confirmatory validation study confirmed the original six-factor structure and the discriminative validity. The final shortened ITSQ contains 25 items, which may be reported as a total score or as 6 subscale scores. CONCLUSION: The ITSQ is a comprehensive and psychometrically valid instrument covering six distinct dimensions of treatment satisfaction with insulin. It is applicable to type-1 and 2 diabetes patients and a wide range of insulin regimens.