Diabetes mellitus has been declared to be at an epidemic level by the World Health Organization. The syndrome is characterised as either Type I (insulin-dependent) or Type II (non-insulin-dependent) diabetes mellitus. Impaired glucose tolerance for extended periods of time results in serious complications such as kidney damage and impaired blood circulation and is the main cause for blindness and amputations in patients with diabetes. A combination of life-style change, dietary change and oral medications can treat Type II diabetes mellitus effectively and prevent long-term complications. Combination therapy appears to be the most effective approach in controlling blood glucose levels. This review updates the progress made in medicinal chemistry towards promising biological targets, with the development of a new generation of small molecules having improved efficacy and safety profiles.