Although insulin is the most effective glucose lowering therapy, adherence varies widely. Few studies have investigated this issue over an extended period. This analysis identified factors associated with insulin nonadherence within MOSAIc, a 2-year prospective cohort study. Patients with type 2 diabetes (T2D) who were ≥18 year old and taking insulin for ≥3 months in 18 countries were included. Demographic, clinical, and self-reported data were collected at baseline and over 2 years. Insulin nonadherence was defined as missing any insulin injections within the past 7 days of a clinic visit. Multivariable logistic regression and multiple imputation were used in the analyses. Among 2706 patients, mean ± SD age was 62.1 ± 10.8 years, 50% were female, and 608 (29.3%) were nonadherent at the end of study. These patients were younger (p<.0001), had lower diabetes knowledge test scores (p=.04), were likely to be nonadherent at baseline (p<.0001), used mixed insulin (p=.0003), injected >1 time per day (p=.001), had a worse experience with their insulin delivery system (p=.01), and had poor communication with their physicians compared to adherent patients. After adjustment, age and baseline insulin nonadherence remained significantly different between the 2 groups. In conclusion, this study indicates that among patients with T2D utilizing insulin, younger patients with a history of poor adherence are less likely to be adherent over time.