The present prospective one-year randomized study was conducted to compare soluble human insulin, with a new rapid-acting human insulin analogue, lispro, with respect to postprandial glucose excursions, frequency of hypoglycaemic episodes, glucose control, and long-term safety in 39 subjects (20 females, 19 males) with Type 1 diabetes. The duration of diabetes, gender distribution, and age were similar in the two groups. The total number of hypoglycaemic episodes was significantly less (p < 0.04, Wilcoxon rank sum test) in subjects receiving insulin lispro compared with regular human insulin over the 12-month period. The 2-h postprandial glucose excursion at 1 year was also significantly less (p < 0.05, ANOVA) in the group treated with insulin lispro. The reductions in the total number of hypoglycaemic episodes and in the postprandial glucose excursion with use of insulin lispro may be beneficial for the long-term management of subjects with Type 1 diabetes. However, the greatest benefit identified by the subjects receiving insulin lispro was the greater convenience of the rapid-acting analogue.