The objective of this Canadian observational study was to assess the safety and patient satisfaction with the ClikSTAR(®) (sanofi-aventis, Frankfurt am Main, Germany) reusable insulin pen in clinical practice. Patients with diabetes (n=2,517) were recruited from 103 sites, provided with the ClikSTAR pen, and instructed to report product technical complaints (PTCs), product technical failures (PTFs), and adverse events (AEs) over 6-12 weeks of use. A patient subgroup (n = 301) completed a pen use questionnaire at 12 weeks. The risk acceptance criterion was that no validated PTF led to a serious AE (SAE). PTFs were PTCs having a confirmed technical deficiency. Patients (68.5% with type 2 diabetes) had a mean age of 56.2 years, and 92.5% were insulin pen users. In total, 84 PTCs were reported by 79 (3.1%) patients. Most PTCs were due to pen handling errors. PTCs from 12 patients were possibly related to AEs, three of which were SAEs; none was confirmed to be due to a PTF. The single reported PTF was not related to an AE/SAE. In the substudy, 97.0% and 95.3% of patients rated "ease of learning" and "ease of use" of the ClikSTAR pen as excellent or good, respectively. Mean scores for patient satisfaction, convenience, flexibility, and recommendations of current treatment on the Diabetes Treatment Satisfaction Questionnaire (change version) had positive changes ranging from 1.0 to 1.8. With ClikSTAR, PTCs were infrequent, and there were no PTFs associated with AEs, demonstrating that the pen is reliable and safe with high levels of patient acceptance and satisfaction.