Objective: Understanding what Insulin Delivery System (IDS) features are important to patients with type 2 diabetes (T2DM) is essential to the development of improved IDSs. The objective of this study was to determine what characteristics are associated with (or predict) users of insulin pens vs. vial and syringe (V/S). Methods: Patients with T2DM were administered a web-based survey that included questions about demographics, comorbidities, glycemic control, and insulin use; ratings of the importance of 12 IDS features; and an evaluation of features of the current IDS. Two logistic regression analyses were performed with the respondent characterization of their IDS as insulin pen or V/S as dependent variables. Variables significantly (p<0.05) associated with dependent variables, a priori, were included as independent variables. Results: A total of 681 insulin-using T2 patients in the US (52% female; mean age=57 years; 88% Caucasian; 85% on insulin >1 year, 86% used V/S) participated in the survey. Significant predictors (p<0.05) for insulin pen use: Patient: “is a homemaker” (OR, 0.177), “agrees their IDS does not interfere with plans for short trips” (OR, 5.942), “agrees their IDS is easy to carry away from home” (OR, 0.054), “rates their IDS ease to carry away from home as ‘important'” (OR, 2.558), “uses Byetta” (OR, 0.067), “injects insulin >twice/day” (OR, 0.235), “has never been diagnosed with depression” (OR, 0.367). Significant predictors (p<0.05) of V/S use: Patient: “is dissatisfied with their IDS regarding insulin use” (OR, 111.767), “disagrees their IDS makes it easy getting ready for next dose” (OR, 0.006), “has cancer” (OR, <0.0001), “uses Glargine” (OR, <0.0001), “is not using insulin lispro” (OR, 0.013), “has a higher number of adults in the household”, “rates IDS discreetness as ‘least important'” (OR, 206.347). Conclusion: Overall, multiple injections and need for portability predict insulin pen use; not valuing discreteness and dissatisfaction predict V/S use.