Hypoglycemia has for the most part been studied inadequately for both of the commonly used long-acting insulin analogs in type 1 and type 2 diabetes. Almost all existing trials have been designed to investigate changes in glycemic control and not differences in hypoglycemia events. In this review, we present an overview of the hypoglycemic data available from the randomized controlled trials comparing insulin glargine and insulin detemir with NPH or continuous subcutaneous insulin infusion in type 1 and type 2 diabetes. The limited head-to-head glargine versus detemir data are also discussed with comments on early results relating to the newer insulin analog, degludec. Basal insulin analogs are associated with reduced nocturnal hypoglycemia in both type 1 and type 2 diabetes. Most studies have excluded participants with impaired awareness of hypoglycemia or previous severe events, however, and hypoglycemia reporting is variable and inconsistent. This limits interpretation for those with long-duration type 1 diabetes, and particularly impaired awareness of hypoglycemia, or long-duration more insulin-deficient type 2 diabetes. New optimally designed studies are required to elucidate the true impact of basal analogs on hypoglycemia burden in those living with long-term insulin therapy.