To assess the efficacy of treatment with oral desmopressin (DDAVP), 20 patients, aged 5-20 y, with central diabetes insipidus were studied during 3 d of hospitalization and for 3 months at the outpatient clinic. At baseline the median rate of diuresis was 12.7 ml kg-1 h-1. Urinary output decreased significantly under treatment with an increase in urinary osmolality, normalization of plasma osmolality and absence of nocturia. Patients were discharged from hospital with a median dose of 500 micrograms d-1 (100-1200 micrograms d-1). An adjustment in dosage was necessary in seven patients during follow-up, resulting in a final dose of 600 micrograms d-1. Body weight and DDAVP doses (r = 0.75, p = 0.001) and body surface and DDAVP doses (r = 0.72, p < 0.001) were significantly correlated. The average dosage was 474 +/- 222 micrograms m-2 d-1 (mean +/- SD). The oral DDAVP treatment remained effective during the 3 months of follow-up. This therapy offers an alternative for the treatment of central diabetes insipidus in children.