64 diabetic patients measured their own blood-glucose concentration with "Dextrostix' (Ames) and an 'Eyetone' (Ames) meter. The records made at home by 53 of these patients have shown that this led to a significant improvement in blood-glucose control. A majority (64%) were able to maintain "good" control (80% of blood-glucose recordings equal to or less than 10 mmol/l for periods as long as 478 days). This hitherto unobtainable degree of control of blood-glucose was achieved mostly with conventional insulin regimens of twice-daily 'Actrapid' (Novo Laboratories Ltd.) and 'Leo-Retard' (Leo Laboratories Ltd.). Adjustments of insulin dosage and type were found to be much easier and more predictable than with urine-glucose analysis. No significant complications were encountered. Hypoglycaemic episodes were less frequent. 70% of patients preferred blood-tests to urine tests and 92% would like to buy their own meter "if the price was right." The results suggest that self-monitoring of blood-glucose by diabetics makes possible, for the first time, the achievement of near normoglycaemia. This may reduce the incidence of long-term diabetic complications.