Currently available antihyperglycemic agents, despite being effective, provide inadequate glycemic control and/or are associated with side effects or nonadherence. Canagliflozin, a widely used orally active inhibitor of sodium-glucose cotransporter 2 (SGLT2), is a new addition to the therapeutic armamentarium of glucose-lowering drugs. This review summarizes findings from different clinical and observational studies of canagliflozin 300 mg in patients with type 2 diabetes mellitus (T2DM). By inhibiting SGLT2, canagliflozin reduces reabsorption of filtered glucose, thereby increasing urinary glucose excretion in patients with T2DM. Canagliflozin 300 mg has been shown to be effective in lowering glycated hemoglobin, fasting plasma glucose, and postprandial glucose in patients with T2DM. Canagliflozin 300 mg also demonstrated significant reductions in body weight and blood pressure and has a low risk of causing hypoglycemia, when not used in conjunction with insulin and insulin secretagogues. Canagliflozin 300 mg was generally well tolerated in clinical studies. The most frequently reported adverse events include genital mycotic infections, urinary tract infections, osmotic diuresis, and volume depletion-related events.