Type 2 diabetes mellitus (T2DM) and obesity commonly co-exist. Improved clinical management of T2DM and improved glycaemic control with traditional therapies including insulin usually result in some weight gain - a frequently perceived barrier to the introduction of insulin by both patient and healthcare professionals. Weight gain of 2.5 kg per 1% change in haemoglobin A(1c) (HbA(1c)) is common in many studies. Strategies to minimize weight gain, particularly in obese patients, are essential to help patients better manage their diabetes and improve quality of life. Insulin analogues with lower risk of hypoglycaemia and better within-patient variability compared with human insulin may help facilitate reaching treatment goals. Moreover, weight gain can be minimized by earlier insulinization and the use of basal insulin, such as insulin glargine, instead of premixed insulin. Data specific to the obese patient with T2DM are presented; they are currently limited but do indicate that insulin glargine therapy is associated with improved glycaemic control as well as less weight gain than other insulins, such as premixed insulin and prandial insulin regimens. Retrospective subanalyses of earlier trials and ongoing studies would shed further light on the impact of insulin therapy in obese people with T2DM in addition to determination of optimal therapeutic strategies.