Background: Vegetative dysfunction is observed in 60-90% of the children presenting with chronic respiratory diseases. Its timely identification and correction increases the effectiveness of the combined rehabilitative treatment of such patients. Material and methods. The vegetative regulation was dynamically evaluated by the analysis of the heart rate variability in 95 patients presenting with bronchial asthma and chronic nonspecific lung diseases. The age of the patients varied from 7 to 16 years. Sixty children received the combined treatment including enteral oxygen therapy, the control group was comprised of 35 patients. Results. The enteral oxygen therapy eliminated the vegetative disbalance in 80.0% of the children with bronchial asthma and in 88,0% of those suffering from chronic nonspecific lung diseases. The results of the spectral analysis of heart rate variability indicate that the total spectrum power (TSP) was significantly increased in the patients of the study group. This effect was accompanied by the restructuring of wave frequency ranges pointing out to the enhancement of the activity of the sympathetic-adrenal system. The integral index of adaptive reserves (AR) increased from 2.0±0,6 to 4.7±0,6 points (p<0.001) under the influence of enteral oxygen therapy; this parameter remained practically unaltered in the patients of the control group where it varied from 1.7±0,8 to 2.0±0,9 points (p>0.05). More manifest pronounced positive dynamics was observed in the patients presenting with initial vagotonia and the severe or moderate form of the disease. Conclusion. The present study has demonstrated the favourable influence of enteral oxygen therapy on the vegetative regulation mechanisms and the adaptive potential of the organism. Analysis of the heart rate variability may be a screening method for the evaluation of the effectiveness of the proposed therapeutic modality.