PURPOSE: Type 2 diabetes mellitus has reached epidemic proportions worldwide. Many patients with type 2 diabetes mellitus will require insulin, and the evidence-based use of insulin is described in the prescription drug label. Product labels in different countries may provide inconsistent information. We evaluated the variability in drug label content for one brand of basal insulin across diverse settings. METHODS: We examined the drug label content pertinent to effective and safe use of insulin glargine across 17 countries: Abu Dhabi (United Arab Emirates), Argentina, Brazil, Canada, China, Germany, Israel, Italy, Japan, Mexico, Russia, Saudi Arabia, South Korea, Spain, Turkey, UK, and the USA. We compared label characteristics in settings where drug labels were governed by a local regulatory authority versus countries where labels were administered by a regional body or adopted from another locale. RESULTS: All 17 labels cautioned that providers should consider age, illness, diet, and exercise when prescribing. Only two (12%) described care of the fasting patient. Caution was urged for patients with renal or hepatic impairment in 16 (94%) labels. Four (24%) did not describe responses to missed doses, and five (29%) failed to recommend patient counseling about the risk of hypoglycemia. Labels emerging from regional or adopted regulatory bodies reported fewer patients in efficacy studies than did labels from settings with their own drug regulatory agencies (365 +/- 0 patients vs. 3560 +/- 2938, p = 0.04). CONCLUSIONS: There is substantial variation in the content of drug labels for glargine, which may lead to international inconsistency in quality of care for diabetic patients.