Background and aims: While insulin pumps are used by a growing number of patients with diabetes, the occurrence of pump dysfunctions remains poorly quantified and documented. Because of their potential deleterious impact on patient health status, those which need pump replacement need to be more specifically investigated. Thanks to the participation of the main insulin pump providers of our country and the clinical centers taking care of the patients who met pump dysfunctions, we carried out an observational study to evaluate the occurrence, nature and clinical consequences of dysfunctions requesting pump replacements. Materials and methods: A prospective registry involving 25 clinical centers and 16 pump providers was performed to collect information about all insulin pumps which needed replacements, whatever the reason, over a 24-month time period. In all cases including a technical issue affecting pump structure or functioning, further details about presumed cause and impact on patient health condition were investigated by the clinical teams. Declarations of pump replacements were initiated on a secure web case report form by patients’ pump providers and completed by additional medical information from the centers. All data was monitored remotely by the registry officer to ensure data consistency. Results: From 2015 to 2018, 2698 pump replacements due to structure or function defects were declared, including 1494 Medtronic (M) Paradigm, Veo or 640G models, 842 Animas (A) 2020 or Vibe models, and 301 Roche (R) Accu-Chek Spirit Combo or Insight models. Only 40 OmniPod and 20 Cellnovo pump replacements were reported and excluded from further analysis. Patients wearing replaced pumps were aged 41.8±19.7, gender: 43% male, 57% female, diabetes: 88% type 1, 10% type 2, 2% other, HbA1c: 7.8±1.2%. Pump age at replacement was 28.1±19.7 months (M=27.5±15.8, A=28.1±16.3, R=35.5±20.3). About 79% replacements (2135) were associated with a pump dysfunction (M=78%, A=85%, R=67%). Main components involved were: screen (A=50%), protection case (M=30%, A=20%) and blocking alarm (R=22%, M=20%). Presumed causes were manufacturing defects (10%), accidental drops (8%), oldness (8%), misuse (7%) or unknown (66%). Problem severity was reported by the clinicians as minor in 58% of cases, major in 13% (disturbed insulin delivery) and blocking (impossible insulin delivery) in 24% (including M=29%, A=15%, R=19%). No clinical consequence was observed in 66% of cases and 24% remained unknown. Hyperglycemia was declared for 9% of cases and hypoglycemia for 1%. 12% of the patients had to switch to multi-daily injections for less than 24 hours in 77% of cases before pump replacement. Hospitalization occurred in 5 cases and ketoacidosis only once. No correlation between pump needed change and age, gender, HbA1c, observance or profession was found. Conclusion: Insulin pump dysfunctions requesting replacement are frequent and reduce expected pump life duration. Some components, especially screen and protection case, appear to lack robustness. Clinically-significant consequences remain rare thanks to quick replacements performed by the pump providers. Because of the frequent launching of new pump models and the impact of pump replacements on healthcare cost, a continuous vigilance should be considered by health authorities to improve pump manufacturing and preserve safety.