Liraglutide (Victoza) is an acylated analogue of glucagon-like peptide-1 (GLP-1) indicated for the treatment of type 2 diabetes mellitus. In phase III studies, once-daily subcutaneous liraglutide improved glycaemic control compared with placebo or active comparator in adult patients with type 2 diabetes, both as monotherapy and in combination with one or two oral antidiabetic drugs such as metformin, sulfonylureas or thiazolidinediones. Liraglutide provided significantly better glycaemic control than rosiglitazone or insulin glargine in combination trials. At appropriate dosages, liraglutide was noninferior to glimepiride with respect to glycaemic control in a combination trial, but provided significantly better control than glimepiride or glibenclamide in monotherapy trials. Liraglutide improved pancreatic beta-cell function, generally led to weight loss, and was associated with a low risk of hypoglycaemia. Liraglutide was generally well tolerated, with the most common adverse events being gastrointestinal events, such as nausea, which decreased over time. Thus, liraglutide is an effective treatment option for use in patients with type 2 diabetes mellitus.