To investigate the influence of two insulin administration modalities, continuous subcutaneous insulin infusion (CSII) and multiple daily insulin injections (MDI) therapy with insulin analogues, on the development of insulin antibodies (IAs) in patients with type 1 diabetes mellitus and to assess the impact of IAs on glucose control and hypoglycaemia. 96 patients with type 1 diabetes mellitus treated with CSII (n = 48) or MDI (n = 48) were included in the study. Age, duration of diabetes, A1c, preprandial and postprandial blood glucose and hypoglycaemic events were compared between IA positive and negative patients. IA levels were higher in the CSII group (% 24.6 +/- A 14.2) than the MDI group (% 13.2 +/- A 9.9). Duration of diabetes and age were not associated with IA positiveness. While A1c, preprandial blood glucose and the frequency of hypoglycaemic events were similar in two groups, postprandial blood glucose was lower in IA positive group (P = 0.03). Patients with type 1 diabetes mellitus treated with CSII with insulin analogues had higher IA levels when compared to MDI therapy. However, the development of IAs did not impair the glycaemic control.