OBJECTIVES: To develop a specific questionnaire to assess the impact of hypoglycemia on the health-related quality of life (HRQoL) of patients with type 2 diabetes mellitus (T2DM). METHODS: A first version of the QolHypo questionnaire was obtained from a literature review and focus groups with patients and physicians. QolHypo consisted of 37 specific items about the impact of hypoglycemia on HRQoL with 5 response categories. The final version was obtained by item reduction methods:  floor and ceiling effects and Rasch analysis. Rasch methodology allowed obtaining a questionnaire which responses will be a trade-off between respondent's abilities and item difficulty. Rasch assesses the appropriateness of item responses with probability curves that must appear ordered as the response categories. Overlapped categories suggested excess of response options and were reduced and items with disordered categories were eliminated. The goodness of fit of items in the Rasch model was calculated using the normalized Infit and Outfit statistics whose interval of good fit is (-2, 2). Items with statistics falling outside that interval were removed. Analyses were performed on a sample of 140 patients. RESULTS: