The objective of the work was to evaluate the effect of short-term hospitalization on metabolic compensation in type 1 diabetics with an intensified insulin regime who are admitted to hospital with the main purpose to participate in an intense educational and therapeutic programme. Twenty patients were examined, mean age 26.3 +/- 6.5 years, mean duration of diabetes 13.2 +/- 8.0 years, who participated in a 5-day educational therapeutic programme which takes place in the authors' department. The level of metabolic compensation was evaluated at the onset and at the end of the hospitalization by means of fructosamine (F), mean blood sugar level, Michaelis index, MAGE (mean amplitude glycaemic excursion), the M value, MDD. During hospitalization in the whole evaluated group an average 6% drop of F was recorded. In the sub-group of patients with a baseline F > 2.6 mmol/l a statistically significant decline occurred from 2.91 +/- 0.14 mmol/l to 2.44 +/- 0.31 mmol/l (p < 0.05). The changes of different indexes calculated from the whole group did not reach statistical significance. In the sub-group with a poorer compensation (F > 2.6 mmol/l), however, the mean blood sugar level declined from 13.48 +/- 2.45 mmol/l to 9.17 +/- 2.05 mmol/l (p < 0.05) and the M value improved from 141.4 +/- 56.6 to 60.5 +/- 40.7 (p < 0.05). The MAGE index deterioration significantly during hospitalization only in the sub-group with a baseline F < 2.6 mmol/l from 2.70 +/- 1.11 to 3.65 +/- 1.28 (p < 0.05). The results indicate that in patients with type 1 diabetes mellitus short-term hospitalization with an educational therapeutic programme need not be associated with a deteriorated metabolic compensation. In those whose compensation is unsatisfactory marked improvement is recorded.