We propose a rational regimen for management of non-insulin-dependent pregnant diabetics (NIDD), using appropriately constituted calorie-restricted diets with the oral agents metformin and glibenclamide as may be necessary, with rapid recourse to insulin if the latter do not produce excellent control of blood glucose. Using this regimen between June 1974 and December 1983 we have managed 423 new diabetics (ND, diagnosed during pregnancy) with a perinatal mortality (PNM) of 14 per 1000 and 268 established diabetics (known diabetics, KD) with a PNM of 70/1000 (57/1000 since 1978). A further 80 NIDDs were 'untreated', i.e., not seen by us until near term; these suffered a PNM of 313/1000. Side-effects of the drugs have been few and mild, they are not teratogenic; 'starvation ketosis' does not occur; neonatal hypoglycaemia is preventable by using continuous insulin infusion during delivery. We suggest that the regimen outlined here is acceptable to the patients, is safe, gives excellent results and furthermore teaches the diabetic mother proper dietary control and combats lifelong obesity. It should be useful especially in developing countries in which pregnant, overweight NIDDs are common. Precise control of the blood glucose is essential.