The use of continuous glucose monitoring (CGM) systems and continuous subcutaneous insulin infusion (CSII) devices adhering to the skin can lead to skin reactions. The objective was to determine the prevalence and consequences of skin reactions at CGM or CSII sites in a large unbiased population. This is a cross-sectional multicenter study. All adult patients with diabetes seen in consultation over a period of 7 months and using or having used a system with skin adhesives (in the last 10 years) were included and filled out a self-assessment questionnaire. Among 851 patients, skin reaction was reported in 28% with CGM and 29% with CSII. Patients reporting reactions were more frequently women using CGM and CSII, and CGM users had type 1 more often than type 2 diabetes ( < 0.001). Manifestations were similar for reactions to CGM and CSII: redness and pruritus in 70%-75% of patients with reactions, pain in 20%-25%, and vesicles and desquamation in 12%-15%. Manifestations occurred within the first 24 h of first use in 22%-24% of patients with reactions to CGM and CSII, but after more than 6 months in 38% and 47% of patients with reactions to CGM and CSII, respectively. Device use was definitively stopped in 12% of patients with reactions to CGM (3.2% of all users) and 7% with reactions to CSII (2.1% of all users). Skin reactions were common, with similar presentations in CGM and CSII users. Manifestations suggested skin irritation rather than allergies. These reactions rarely led to the definitive discontinuation of the use of the device.