Introduction. The article assessed the effectiveness of decimeter wave therapy (DWT) in the postoperative period after laparoscopic appendectomy for destructive appendicitis in children. Authors relate positive clinical effects with the activation of mitochondrial energy metabolism. Material and methods. The study included 132 patients (46 destructive appendicitis cases, 86 h appendicular peritonitis patients). Among them, there were 75 (56.8 percent) boys and 57 (43.2 percent) girls aged of from 3 to 17 years (mean age of 10.7 ± 3.07 years). Patients of the main group received DWT procedures with the use of the apparatus DMV-02 “Solnyshko” starting from the 1st day after the surgery. Patients from the reference group received no physiotherapy treatment. The activity of dehydrogenases of lymphocytes (succinic dehydrogenase (SDH) and NADH-dehydrogenase) in patients from the main group and the comparison group were determined by means of cytomorphological method with the use a hardware-software visualization complex “Videotest” and the “Morphology 5.2” (Russia), at the 1st, 3rd and 5th day of the postoperative period. Results. Under the influence of DWT in the postoperative period the frequency of intestinal insufficiency syndrome, systemic inflammatory response syndrome, infiltrative adhesions was established to decline. There was noted a gain in the activity of mitochondrial enzymes, reflecting the first and second stages of the respiratory chain (SDH and NADH-dehydrogenase). In children with destructive appendicitis against the background of DWT, the normalization of the activity of LDH in moderate activation of NADH-dehydrogenase, and in appendicular peritonitis cases - the significant elevation in LDH activity of lymphocytes and activation of NADH-dehydrogenase occurs. In patients from the main group, the absolute number of peripheral blood lymphocytes normalized Conclusion. Under the influence of DWT there was noted the activation of enzymes of mitochondria that provides a mild course of the postoperative period.